Tesi: "Stratigraphic Eocene"

1

Byrnes, Mark Edward. "Provenance study of late Eocene arkosic sandstones in southwest and central Washington." PDXScholar, 1985. https://pdxscholar.library.pdx.edu/open_access_etds/3405.

Testo completo

Abstract (sommario):

The purpose of this study is to compare the sandstone composition and trace element geochemistry between samples representing the Summit Creek sandstone, Naches, Chumstick, and Carbonado Formations in order to determine if these sediments were all derived from the same provenance, and to determine the composition of the source rocks in hopes to identify the present day location of the source areas.

Gli stili APA, Harvard, Vancouver, ISO e altri

2

McClincy, Matthew John. "Tephrostratigraphy of the middle Eocene Chumstick Formation, Cascade Range, Douglas County, Washington." PDXScholar, 1986. https://pdxscholar.library.pdx.edu/open_access_etds/3633.

Testo completo

Abstract (sommario):

This study outlines the ash (tuff) bed stratigraphy (tephrostratigraphy) in the middle Eocene Chumstick Formation of central Washington. The tuff beds provide local marker beds enabling interpretation of the stratigraphy and structure of the formation. The chemical signature of these units provides the basis on which the units can be traced over broad areas in the basin of deposition. Correlations of tuff beds were obtained over distances of 41 km.

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Cunderla, Brent Joseph. "Stratigraphic and petrologic analysis of trends within the Spencer Formation sandstones : from Corvallis, Benton County, to Henry Hagg Lake, Yamhill and Washington counties, Oregon." PDXScholar, 1986. https://pdxscholar.library.pdx.edu/open_access_etds/3588.

Testo completo

Abstract (sommario):

Within the thesis study area Spencer Formation arkosic/arkosic lithic sandstone lithofacies of Narizian age crop out in a sinuous north-northwesterly band from the Corvallis area into the Henry Hagg Lake vicinity ten kilometers southwest of Forest Grove, Oregon.

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Vinyoles, i. Busquets Andreu. "Sediment routing systems of the Eocene Tremp-Jaca basin: Stratigraphic analysis and numerical models." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/672479.

Testo completo

Abstract (sommario):

The Eocene South-Pyrenean foreland basin provides a continuum of outcrops representing a Source to Sink sediment routing system from subaerial canyons to deep marine environments. On this context, the specific objective of this study is: (a) to contribute to the knowledge of the chronostratigraphy and the basin infill of the study area; (b) to analyze the evolution of the sedimentation rates on the Tremp-Jaca basin; and (c) to generate numerical models to (i) assess the sediment routing and sediment balance and, (ii) to evaluate the basin response to the propagation of climatic and tectonic signals. Two new magnetostratigraphic sections are built on the Tremp-Jaca basin; the Olsón (Ainsa basin) and the Yebra de Basa sections (Jaca basin). The Olsón section provides a late Lutetian to early Priabonian age for the Escanilla formation in the Ainsa basin, and the same age range is provided on the Yebra de Basa section for the strata encompassed between the Sabiñánigo sandstone and the Santa Orosia formation. The age constrains provided by these new sections and the data sorted from a systematic review of the literature have been used for an analysis of the sedimentation rates in the Tremp-Jaca basin. The studied sections were decompacted by backstripping to correct the differential burial compactions between the sections. This study shows that sedimentation rates may not show the expected variations related to depozone distribution. This lack of correlation between the depozones and the sedimentation rates are consequence of the lagged response to deformation front shifts and the complexity in the structure of the wedge-top. This complexity result in a widespread subsidence related to the emplacement of basement units in the hinterland. Also underfilled forelands may develop high sedimentation rates in the initial stages of wedge-top as basin gradients are a continuation to those developed in the previous foredeep phase. Sedimentation rates in overfilled areas are controlled by accommodation. In underfilled areas, the main control is clastic supply. During graded shelf regressive stages, maximum sedimentation rates are in foreset areas. In the transgressive stages, maximum sedimentation rates are at the topset. In out-of-grade periods, high sedimentation rates are in deep marine areas. The results obtained above have been used to feed forward stratigraphic models, using Dionisos software, to test and understand the different parameters affecting the sedimentary infill of the basin. A first model on the sediment routing systems of the Tremp-Jaca basin, based on the data from the sedimentation rates analysis, succeeds on reproducing the sedimentary routes that can be deduced from the paleocurrent patterns on the Tremp-Jaca basin, validating the inputted data. A second forward stratigraphic model, based on architectural and cyclostratigraphic analysis from previous works, determines that the high-frequency Milankovitch cyclicity of the Belsué-Atarés delta (Sierras Exteriores) is primarily forced from the sediment supply and secondary from the eustasy. A les conques Eocenes Sudpirenaiques d’avantpaís hi ha un continu d’afloraments representatius de les rutes sedimentàries del sistema Source to Sink, des de canons subaeris fins a ambients marins profunds. En aquest context, aquest estudi té com a objectiu (a) contribuir al coneixement de la cronoestratigrafia i el reompliment de les conques de l'àrea d'estudi; (b) analitzar l’evolució de les taxes de sedimentació a la conca de Tremp-Jaca; i (c) generar models numèrics per (i) avaluar les rutes sedimentàries i el balanç sedimentari i (ii) avaluar la resposta de la conca a la propagació de senyals climàtics i tectònics. S’han construït dues noves seccions magnetostratigràfiques a la conca de Tremp-Jaca; les seccions d’Olsón (conca d’Aïnsa) i de Yebra de Basa (conca de Jaca). La secció d’Olsón proporciona una edat Luteciana superior fins a Priaboniana inferior per a la part superior de la formació Escanilla a la conca d’Aïnsa. A la secció de Yebra de Basa s’obté la mateixa franja d’edat pels estrats entre el gres de Sabiñánigo i la formació de Santa Orosia . Les edats proporcionades per aquestes noves seccions i les dades obtingudes a partir d'una revisió sistemàtica de les dades publicades, s'han utilitzat per a una anàlisi de les taxes de sedimentació de la conca de Tremp-Jaca. Les seccions estudiades han estat descompactades per backstripping per corregir l’enterrament diferencial que resulta en estadis de compactació diferents entre les seccions estudiades. Aquest estudi mostra que les taxes sedimentaries poden no mostrar les variacions esperades en relació a la distribució de les depozones. Aquesta manca de correlació entre les depozones i les taxes de sedimentació són conseqüència del retard en la resposta als canvis en la posició del front de deformació al wedge-top. Aquesta complexitat resulta en l’expansió de la subsidència relacionada amb l’emplaçament d’unitats basals al hinterland. Aquesta complexitat resulta en una major subsidència relacionada amb l’apilament d’unitats basalts al hinterland. També les conques d'avantpaís underfilled poden desenvolupar altes taxes de sedimentació en els estadis inicials del wedge-top, ja que els gradients sedimentaris són la continuació dels desenvolupats a la fase de foredeep anterior. Les taxes de sedimentació a les àrees overfilled estan controlades per l’acomodació. A les àrees underfilled, el control principal és l’aport de sediments. Durant els episodis regressius de les plataformes gradades, les taxes de sedimentació màximes es donen al topset. En els períodes no-gradats, les taxes de sedimentació més elevades es troben a les àrees marines profundes. Els resultats obtinguts s’han utilitzat per alimentar dos forward stratigraphic models, utilitzant el software Dionisos, per provar i entendre els diferents paràmetres que defineixen el reompliment de la conca. Un primer model en els sistemes de rutes sedimentàries de la conca de Tremp-Jaca, basat en les dades provinents de l’anàlisi de les taxes de sedimentació, té èxit en reproduir les rutes sedimentàries que es poden deduir dels paleocorrents de la conca de Tremp-Jaca, validant les dades introduïdes. Un segon model, a partir de dades arquitecturals i cicloestratigràfiques de treballs previs, determina que les ciclicitats de Milankovitch d’alta freqüència del delta de Belsué-Atarés (Sierras Exteriores) són primàriament forçats per l’aport sedimentari i secundàriament per l’eustàcia.

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Schmidt, Rolf. "Eocene bryozoa of the St Vincent Basin, South Australia - taxonomy, biogeography and palaeoenvironments /." Title page, abstract and contents only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phs3491.pdf.

Testo completo

Abstract (sommario):

Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Geology and Geophysics, 2003? Includes Publication list by the author as appendix A. "July 2003." Includes bibliographical references (leaves 308-324).

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Farr, Leonard Carl Jr. "Stratigraphy, diagenesis, and depositional environment of the Cowlitz Formation (Eocene), northwest Oregon." PDXScholar, 1989. https://pdxscholar.library.pdx.edu/open_access_etds/3905.

Testo completo

Abstract (sommario):

The Upper Eocene Cowlitz Formation is exposed in surface outcrops southwest of the town of Vernonia, in Columbia County, Oregon. The Cowlitz Formation also occurs in the subsurface of the Mist gas field where its Clark and Wilson (C and W) sandstone member (informal) acts as a natural gas reservoir, and its upper Cowlitz mudstone member (informal) acts as a cap rock. Surface exposures and continuous core were studied in order to determine Cowlitz Formation stratigraphy, and its depositional environment. Fresh core samples were also studied petrographically, and with a scanning electron microscope, in order to determine the effects of diagenesis in the gas producing C and W sandstone member.

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Matoush, Joseph P. "The Stratigraphic, Sedimentologic, and Paleogeographic Evolution of the Eocene- Oligocene Grasshopper Extensional Basin, Southwest Montana." DigitalCommons@USU, 2002. https://digitalcommons.usu.edu/etd/6726.

Testo completo

Abstract (sommario):

Grasshopper basin, located in southwest Montana, is an east-tilted graben bounded by the listric Muddy-Grasshopper fault and the Meriwether Lewis fault on the eastern and western margins of the basin, respectively. This basin contains a complex stratigraphy of intertonguing facies comprised of five unconformity-bounded sequences of Tertiary alluvial, flu vial, deltaic, and lacustrine sedimentary and volcanic rocks. Sequence 1 consists of the Challis volcanic Group (Middle Eocene). The sedimentary rocks of the Medicine Lodge beds (Late Eocene-Late Oligocene) represent sequence 2 and approximately 90% of the basin-fill within Grasshopper basin. Sequence 3 consists 11 of the Sedimentary Rocks of Everson Creek (Late Oligocene-Early Miocene), sequence 4 is represented by the Sedimentary Rocks of Bannack Pass (Middle-Late Miocene), and the Six Mile Creek Formation (Late Miocene?) corresponds to sequence 5. Sequence 2 is the synrift deposit for the Muddy-Grasshopper fault, and was dominated by lakes that filled axially by rivers from the north. Transverse sediment influx was present on small fan-delta complexes shed into the lake from the eastern margin and periodic large fluvial-dominated alluvial fan and deltaic deposition from the western margin. Paleocurrent analyses are consistent with these observations and show predominantly south-southeastward axial paleoflow directions with west-directed and east-directed paleoflow on the eastern and western margins, respectively. Petrologic studies, including sandstone petrography and conglomerate petrology, reveal a mixed "basement uplift" and "recycled orogen" tectonic provenance. These findings support a model for Eocene-Oligocene rifting characterized by moderate to high relief superimposed on the Cretaceous-Early Tertiary Sevier fold-and-thrust belt. Paleogeographic reconstructions of Grasshopper basin reveal the lack of a southern basin margin. A correlation of the basin-fill contained in the Medicine Lodge and Horse Prairie basins to the south with the Medicine Lodge beds (sequence 2) in Grasshopper basin suggests that each of these basins represents a third of a larger preexisting extensional basin that was partially dismembered by later phases of continued extension. Large extensional folds in Grasshopper basin had a small influence on facies architecture in the basin.

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Gregory, Kathryn Mary. "Late Eocene paleoaltitude, paleoclimate, and paleogeography of the Front Range region, Colorado." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185985.

Testo completo

Abstract (sommario):

Erosion beveled the Laramide Front Range uplift in Colorado to a surface of low relief by the end of the Eocene. This study uses paleobotanic climate analysis techniques to determine the paleoelevation of this regional surface by examining the overlying 34.9 Ma Florissant flora. Multiple regression models explaining 93.4% of the variance in mean annual temperature (MAT), 86.1% of the variance in growing season precipitation (GSP) and 65.7% of the variance in rainfall distribution were derived from J. A. Wolfe's dataset of 31 leaf physiognomic character states from 86 modern vegetation sites. When applied to a new collection of 29 species from the Florissant flora, estimates of MAT = 10.7 ± 1.5°C, and GSP = 55.6 ± 12.5 cm, with precipitation occurring mostly during the growing season, are derived. This paleoclimate estimate is corroborated by data from late Eocene Sequoia affinis from Florissant. Higher mean ring width of the fossil trees as compared to modern counterparts can be explained by a climate with summer mean monthly temperatures ≥ 14°C and summer mean monthly rainfall >1.5 cm. The estimated MAT, when combined with coeval sea level MAT and terrestrial lapse rate, implies an elevation of 2.3-3.3 km for Florissant, which is indistinguishable from the modern elevation of 2.5 km. The elevation of Florissant is tied to that of the Great Plains by the Wall Mountain Tuff, so the Great Plains were also high. The elevation was created either by underplating and/or mass transfer in the Laramide, or by mantle uplift of crust thickened by pre-Laramide tectonics. This elevation estimate implies that: (1) Pliocene uplift is not required to explain the present elevation. Thus, late Tertiary plateau uplift in the western US was not a contributing factor to the marked global cooling since 15 Ma; and (2) in the late Eocene, regional surfaces of planation could be formed at elevations significantly above sea level but below tree line. The surface was possibly formed from a lack of storminess; a preponderance of small storm events will diffusively smooth topography.

Gli stili APA, Harvard, Vancouver, ISO e altri

9

Ressel, Michael W. "Igneous geology of the Carlin Trend, Nevada the importance of Eocene magmatism in gold mineralization /." abstract and full text PDF (free order & download UNR users only), 2005. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3210296.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Robinson, Andrew Mark. "Stratigraphic development and controls on the architecture of Eocene depositional systems in the Faroe-Shetland Basin." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55054/.

Testo completo

Abstract (sommario):

A detailed investigation of the Eocene stratigraphy in the Faroe-Shetland Basin was undertaken with a view to developing a basin-wide seismic-stratigraphic framework in order to describe the palaeogeographic evolution and depositional architecture of the basin. This study has tested the applicability of sequence stratigraphy on a regional and local scale and outlines the major depositional controls on the succession. Integration of seismic, well and biostratigraphic data has allowed for the identification of four regionally correlatable seismic-stratigraphic units which document the basin fill history. Depositional systems are controlled by the interaction of fluctuating relative sea-level and local tectonic controls. Early Eocene uplift on compressional fold structures, inherited Mesozoic palaeobathymetry, dynamic uplift from mantle plume activity and prograding lava deltas all control the distribution, thickness and facies of the Eocene succession. Case studies from a basin margin and intra-basinal setting have provided detailed evidence of the localised sedimentary response to changing basin conditions. The use of high resolution 3-D seismic data has enabled depositional sequences and the complex seismic geomorphology of palaeo-drainage systems to be recognised. A cyclicity of sedimentary response is observed in a deltaic environment which documents the evolution of relative sea-level on the southern margin of the basin. Classical sequence-stratigraphic techniques have, in places, provided a useful guide to stratigraphic interpretation and analysis. However, attempts to test the widely used sequence stratigraphic model of sequences as regionally correlatable stratigraphic surfaces have failed largely because of the impracticability of correlating seismic reflections on a regional scale. The conclusion from this is that sequence stratigraphy is a powerful analytical tool that can be applied locally, but is likely to encounter significant difficulties on a basinal length scale. This larger scale correlatability is a corollary of the link between sequence development and eustatic sea level changes. In this thesis, this link cannot be substantiated, and local factors predominate.

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Sunnetcioglu, Mehmet Akif. "A Sequence Stratigraphic Approach To The Depositional History Analysis Of The Upper Eocene Sedimentary Succession, Northwest Of The Thrace Basin, Turkey." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609346/index.pdf.

Testo completo

Abstract (sommario):

This study investigates the depositional history of the Late Eocene sedimentary record in the northwest of the Thrace Basin in a sequence stratigraphic approach and estimates the contribution of regional tectonics, basin physiography and eustasy. Late Eocene sedimentary succession was analyzed in two third-order sequences based on two major data sets seismic reflection and well data sets. Depositional Sequence-1, represented by progradational stacking patterns, comprises the coarse-grained Hamitabat turbidite system. The base of the Sequence-1 was defined as the base of channel fill deposits in the northern shelf setting and the base of slope fan deposits in the slope setting. This boundary separates Lower-Middle and Upper Eocene sediments. In the slope setting, the Hamitabat turbidite system was analyzed in three major depocenters Western, Northwestern and Northeastern depocenters respectively. Hamitabat turbidite system was controlled by the interaction of regional tectonics, basin physiography and eustatic fluctuations in the Late Eocene. This study highlighted the role of the regional variables tectonic influence and basin morphology on the submarine canyon formation. The facies distribution was controlled by the high subsidence rate of sea-floor dominantly instead of eustasy. Depositional Sequence-2, represented by mostly retrogradational stacking patterns, is a clastic-carbonate mixed system. Depositional Sequence-2 was subdivided into three higher-order sequences. The lower sequence boundaries were induced by the rapid relative sea-level rise. The upper boundary of the Depositional Sequence-2 was defined as the termination of clastic-carbonate mixed system and a candidate for the Eocene-Oligocene contact.

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Díaz, Poveda Leonardo. "Evolución sedimentaria y estructural del Eoceno superior, Cordillera oriental de Colombia, Sur América." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/396371.

Testo completo

Abstract (sommario):

Colombia se encuentra situada en la esquina NW de Sur América, este sector de gran complejidad tectónica es un margen destructivo por convergencia de placas. Convergen las placas de Suramérica, de afinidad continental, y las placas Pacifica y Caribe, de afinidad oceánica. La complejidad está en que la placa Pacifica subduce a la placa de Suramérica en el sector sur de Colombia y en la parte media colisiona oblicuamente. La placa Caribe colisiona también oblicuamente, generando un régimen transpresivo y en la parte norte colisiona con la placa Suramericana a lo largo de una zona de fallas transformantes dextrales. Las unidades del Eoceno superior en Colombia son el producto de la interacción de las placas tectónicas, las cuales controlaron las condiciones de formación y depositación en las subcuencas. Primero, con base en el levantamiento de columnas estratigráficas de esta secesión, se establecieron secciones de control de las unidades litoestratigráficas, definidas inicialmente por Porta (1974). Se realizó también una división en secuencias deposicionales de tipo Trangresivo –Regresivo T-R que se aplicó al registro sedimentario del Jurásico superior – Holoceno con el fin de poder tener una idea del armazón general de la cuenca. Se determinaron seis secuencias de tercer orden para el mesozoico y cinco de segundo orden para el terciario. La sucesión de interés, Eoceno superior, corresponde a una secuencia deposicional que fosilizaba la superficie de primer orden constituida por la discordancia del Eoceno inferior. Esta secuencia se depositó en tres subcuencas alargadas con dirección del eje NE, a partir de la topografía generada por la inversión de la cuenca mesozoica, lo cual dio lugar a una geometría de subcuencas tipo valles de incisión paralelos entre sí. Los resultados de los estudios de paleocorrientes soportan este resultado y el de un basculamiento hacia el NE con una paleopendiente promedio de 0,006° característica de este tipo de cuencas. Los movimientos verticales datados con huellas de fisión significan el inicio de la etapa contractiva en el Masstrichtiense seguido del clímax de deformación contractiva en el Eoceno inferior, generando los umbrales que separaron las tres subcuencas del Eoceno superior. Las nueve curvas de subsidencia total corregida con la paleobatimetría y la erosión, nos muestran muy bien la evolución de la acomodación sedimentaria durante la etapa Jurásico superior-actual, así mismo reflejan el efecto de carga por apilamiento estructural y flexión en las cuencas de antepaís de los llanos y Valle del Magdalena lo cual se inició alrededor de los 40 Ma (Eoceno superior). La evolución de la cuenca se realizó en cuatro etapas: 1). Extensión paleozoica (Paleozoico Superior), 2). Inversión triásica, 3). Extensión mesozoica. (Jurásico Superior – Cretácico), y 4) Inversión paleógena (Paleoceno superior – Holoceno). Durante esta etapa de inversión la cuenca Jurásico superior – Cretácica sufrió un acortamiento hasta del 55% que equivale a 250 km para llegar al estado deformado actual. La nueva configuración paleogeográfíca generada por contracción compartimentalizó la cuenca cretácica generando las tres subcuencas terciarias. Estas subcuencas desarrollaron sistemas predominantemente fluviales de ríos anastomosados que corrían hacia el N. Los sistemas de abanicos aluviales quedaban junto a las fracturas activas y en la parte cercana a los umbrales más levantados que actuaron de potente área fuente. De las subcuencas del Valle Medio del Magdalena y de la Cordillera Oriental. En determinados momentos las partes septentrionales registran la entrada de facies transicionales de estuario, en los sectores más distales de los sistemas fluviales. Los materiales del Eoceno superior estudiados constituyen el mejor reservorio de todos los sistemas petrolíferos de Colombia. Por esta razón, la caracterización de la roca almacén y su localización y predicción de distribución, es esencial para la exploración y producción de campos existentes y la predicción de nuevos prospectos. A partir del nuevo modelo obtenido para el Eoceno superior, se abren toda una serie de grandes posibilidades para desarrollar nuevos play concepts de estudios exploratorios de hidrocarburos. Colombia is located in the northwest corner of South America, in an área tectonically highly complex as it corresponds to a destructive margin due to the convergence of several plates. There, the South American Plate of continental affinity, and the Pacific and Caribbean plates of oceanic affinity, all converge. The complexity is associated with subduction of the Pacific Plate underneath the South American Plate in the southern part of Colombia, where in the central part the two plates collide obliquely. The Caribbean plate also collides obliquely against the South American Plate, generating conditions characteristic of a transpressive regime; in the northernmost part this collision occurs along a zone of dextral transforming faults. The stratigraphic units corresponding to the late Eocene in Colombia are the product of the interaction of tectonic plates, which controlled basin formation and their subsequent depositional conditions. Porta (1974) firstly defined the lithostratigraphic units based on a series of sections surveyed as part of the fieldwork carried out at the time. Later, a series of transgressive-regressive (T-R) depositional sequences were defined for the late Jurassic-Holocene section, which allowed establishing a general stratigraphic framework of the basin. Thus, a total of six third order sequences for the Mesozoic and five second order sequences for the Tertiary, were defined. The upper Eocene section, as the interval of interest, corresponds to a depositional sequence that buries a first order Surface representing the early Eocene unconformity. This sequence was deposited in three NE trending elongated sub-basins, associated with the paleo topography resulting from the structural inversion process affecting the Mesozoic basin; the resulting relief formed corresponds to a geometry represented by parallel sub-basins representing incised valleys. Paleo current analyses confirm such orientation as well as a major northeast tilting of the area, which exhibits an average paleo-inclination of 0.006°, which characterizes this type of basins. Vertical movements dated through fission track studies indicate that the contractional event started in the Maastrichtian with its climax occurring in early Eocene. This late event generated the highs which separated the three late Eocene sub-basins. A total of nine (9) total subsidence curves were prepared and corrected using paleobathymetry as well as the amount of section removed by erosion. They illustrate very well the evolution of the accommodation space from late Jurassic to Present, and also reflect the load associated with structural piling as well as the flexure on the Llanos and Middle Magdalena basins, which commenced approximately 40 Ma in late Eocene. The evolution of the basin involved four (4) main stages, as follows: 1) Paleozoic extension (Late Paleozoic), 2) Triassic inversion, 3) Mesozoic extension (Late Jurassic-Early Cretaceos), and 4) Paleogene inversion (Late Paleocene – Holocene). During this late stage of inversion, the late Jurassic-Cretaceous basin underwent shortening of 55%, which corresponds to approximately 250 km, before reaching the present-day configuration. The new paleogeographic configuration generated under contractional conditions, compartmentalized the Cretaceous basin creating three tertiary sub-basins. A series of fluvial systems running northwards, including dominantly braided and anastomosed streams, dominated sedimentation in the sub-basins. On the other hand, alluvial fan systems were located along an active fracture system, located next to the structural highs, which were uplifted and acted as provenance areas for the Middle Magdalena Valley and Cordillera Oriental sub-basins. Nevertheless, at certain times the northern portions of the sub-basins witnessed estuarine transitional facies, particularly in the distal parts of the fluvial systems. Upper Eocene sandstones form the best reservoir for all the Colombian petroleum systems Therefore, characterization, location and predicting distribution of reservoirs are fundamental in exploration and field production. The new model proposed for late Eocene reservoirs opens up tremendous potential for the generation of new play concepts, which should be part of any sound hydrocarbon exploration program to be performed in the future.

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Zebari, Bahroz Gh A. "Controls on the spatial and temporal evolution and distribution of depositional components in the Paleocene-Lower Eocene Succession, Kurdistan Region-Iraq." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=239281.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Shaw, Neil B. "Biostratigraphy of the Cowlitz Formation in the upper Nehalem River Basin, northwest Oregon." PDXScholar, 1986. https://pdxscholar.library.pdx.edu/open_access_etds/3654.

Testo completo

Abstract (sommario):

Examination of stream and roadcut exposures of the Cowlitz Formation allows the selection of measured representative sections, and collection of fossils, from an area roughly defined by the intersection of the boundaries of Clatsop, Columbia, Tillamook and Washington counties in Oregon. The study defines the features of the local environment of deposition, correlates sections to derive a composite columnar section, and develops a checklist of species for both microfossils and megafossils of the Cowlitz Formation.

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Brissette, Nicolas O. "The Cocoa Sand member of the Yazoo Formation (Eocene), Mississippi : a petrologic and depositional model study." Virtual Press, 2004. http://liblink.bsu.edu/uhtbin/catkey/1306384.

Testo completo

Abstract (sommario):

The sandstone petrology of the Cocoa Sand Member of the Eocene Yazoo Formation is not well documented. Acquisition of two cores (#1 Ketler and #1 Young) during the Mobil-Mississippi Project of 1993 has provided the opportunity for a detailed petrologic and depositional analysis.The Cocoa Sand Member is a moderate to well sorted, poorly cemented quartz arenite with an average composition of Q% Fo L4. Lithic fragments are dominated by sedimentary rock fragments that appear to be rip-up clasts from the underlying North Twistwood Creek Clay. Quartz grains range from well rounded to angular with embayed anhedral to euhedral grains common. They are often encased in tangential clays indicating a possible reworked sedimentary to volcanic source for this sandstone. Heavy mineral analysis supports a volcanic source, but also indicates a metamorphic contribution.The Cocoa Sand shows little compaction with a packing density averaging 43% and the packing proximity averaging 21%. Point and tangential contacts are predominant as point count porosity averages 18.4%. The dominant authigenic phase is Camontmorillonite with lesser amounts of kaolinite, illite, calcite, and heulandite.Core, petrographic, and log analyses indicates that the Cocoa Sand Member of the Yazoo Formation is an isolated, intrabasinal sheet sand that thickens in the down dip direction. Winnowing of the North Twistwood Creek Member of the Yazoo Formation during transgression resulted in the deposition of the Cocoa Sandstone. This is supported by the similarities in composition between the North Twistwood Creek Member and the Cocoa Sand Member and the presence of rip-up clasts found at the North Twistwood Creek-Cocoa Sand Member contact. It is concluded that the Cocoa Sand Member is the initiation of sequence TE3.3 and here called subset TE3.3a of a transgressive system tract. This subset runs from the base of the Cocoa Sand Member to the bottom of the Pachuta Marl. Department of Geology

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Liu, Shaobin. "Characterization, geographic distribution, and number of upper Eocene impact ejecta layers and their correlations with source craters." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 15.46 Mb., 308 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3220787.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Shackelton, Allison Lee. "REGIONAL AND STRATIGRAPHIC VARIABILITY OF MICROWEAR ON THE MOLARS OF LEPTOMERYX FROM EOCENE-OLIGOCENE STRATA OF WYOMING AND NEBRASKA." Master's thesis, Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/402261.

Testo completo

Abstract (sommario):

Geology M.S. Climate change across the terrestrial Eocene-Oligocene boundary of the Great Plains is recorded by shifts in sediments, facies, paleosols, and isotopic records, and is interpreted as a shift to overall cooler and drier conditions. As an independent test of paleoenvironmental shifts caused by climatic change, I compared microwear on M2 molars of Leptomeryx from the White River Group (WR) at Toadstool Park, Nebraska (n = 9) and Flagstaff Rim, Wyoming (n = 11). Comparisons of microwear were made through time at each section. Various measurements of microwear were quantified on original, uncoated specimens using environmental scanning electron microscopy and Microware 4.0 software, and evaluated with ANOVA and Kruskal-Wallis statistical tests. Values of the scratch:pit ratio, scratch number, feature major:minor axis ratio, feature vector length, major axis standard deviation, major:minor axis standard deviation, and feature orientation standard deviation for Leptomeryx M2 molars are significantly different (p<0.05) between Wyoming and Nebraska. Microwear patterns suggest paleoecological differences between the two locations, possibly related to differences in Leptomeryx diet or in amount or character of sediment adhering to ingested vegetation. Little fossil evidence of vegetation type is preserved at either locality, other than clay-filled root traces or occasional rhizoliths or silicified fragments. However, sediments of the WR are a mixture of volcaniclastic enriched mudstone, siltstone, and sandstone, with generally coarser overall particle sizes in Wyoming that reflect proximity to siliciclastic sources. The degree of overall volcaniclastic enrichment and number of airfall tuffs is also higher at Flagstaff Rim. Paleosols suggest a shift from closed canopy forest to progressively open conditions at each locality and, although microwear differences could result from differences in vegetation or particle sizes of adhered sediments on plants, no or very low correlations between microwear features and stratigraphic level were detected at either locality, indicating that any changes in paleoecology over time did not significantly alter the diets of Leptomeryx, although diet may have been geographically different. Temple University--Theses

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Friedman, Richard M. "Geology and geochronometry of the eocene Tatla Lake metamorphic core complex, western edge of the intermontane belt, British Columbia." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28780.

Testo completo

Abstract (sommario):

The Tatla Lake Metamorphic Complex (TLMC) underlies 1000 km² on the western side of the Intermontane Belt (1MB) northeast of the Yalakom fault Three fault-bounded lithotectonic assemblages are recognized in the area studied: an amphibolite grade gneissic and migmatitic core, structurally overlain by a 1 to 2.5 + km-thick zone of amphibolite and greenschist grade mylonite and ductilely sheared metamorphic rocks, the ductilely sheared assemblage (DSA), which is in turn structurally overlain by weakly deformed to unstrained subgreenschist grade rocks of the upper plate which flank the TLMC on three sides. Structures in the gneissic core include a gneissic foliation and schistosity (Sic), which has been deformed by west to northwest-trending tight to isoclinal folds (F2c). Tectonic fabrics observed throughout the DSA which formed during Ds deformation include a gently dipping mylonitic foliation (Ss), containing a mineral elongation (stretching) lineation (Ls) which trends towards 280° ± 20°. Minor folds of variable trend (Fs), almost exclusively confined to DSA metasedimentary rocks, are interpreted as coeval with ductile shear. Vergence of these folds defines movement sense and direction of top towards 290° ± 20°. Kinematic indicators from DSA rocks which have not been deformed by syn-ductile shear folds indicate a top-to-the-west sense of shear while those deformed by Fs folds yield conflicting results, with a top-to-the-west sense predominating. The entire lower plate comprising the TLMC has been deformed by broad, upright, west to west-northwest trending, shallowly plunging map-scale folds (F3) during D3, which deform Sic and Ss surfaces. The steeply dipping, northwest-trending Yalakom fault truncates all units and structures of the TLMC. Gently to moderately dipping normal faults of Ds and post-D3 relative age are the southern and eastern boundaries between DSA upper plate rocks and 1MB lower plate rocks. U-Pb zircon dates from igneous arid meta- igneous rocks from the lower plate range from Late Jurassic (157 Ma) through Eocene (47 Ma). These dates bracket the timing of Cretaceous (107 Ma to 79 Ma, in the core) and Eocene (55 Ma to 47 Ma, in the DSA) deformation and metamorphism in the lower plate. Biotite and hornblende K-Ai dates of 53.4 Ma to 45.6 Ma for lower plate rocks are in sharp contrast to Jurassic dates from nearby upper plate rocks; they record the uplift and cooling of the TLMC. Whole rock initial ⁸⁷Sr/⁸⁶Sr ratios (and for most samples present-day values) of less ≤0.704 have been determined for igneous and meta-igneous rocks of the TLMC; such values are typical of magmatic arc rocks of the 1MB and Coast Plutonic Complex of B.C. Whole rock major and trace element chemistry of lower plate igneous and meta-igneous rocks indicate sub-alkaline, calcalkaline, volcanic arc affinities. Garnet-biotite temperatures (interpreted as Eocene in age), from pelitic schist in the southern part of the DSA increase from about 400 ± 50 to 650 ± 50 C with increasing structural depth. A GT-BI-QZ-Al₂SiO₅ pressure of 8 ± 3 kb has been calculated for one of these samples. A T-P of 650 ± 50 C and 5.3 ± 3 kb, calculated from inclusions and garnet cores in a small pelitic pendant in the northwest part of the DSA, reflects conditions during intrusion of the surrounding 71 ± 3 Ma igneous body. A pressure of 7.2 ± 1.4 kb, based on the total Al in hornblende, has been calculated for this body. Cretaceous ductile deformation in the gneissic core may be related to folding and thrusting which occured in high level rocks to the west and east of the field area. During Early Eocene time (55-47 Ma) the TLMC acquired the characteristics of a Cordilleran metamorphic core complex. Mylonites of the DSA were emplaced by faulting beneath weakly deformed, low metamorphic grade rocks of the upper plate. Synchronously, metamorphic rocks of the gneissic and migmatitic core of the TLMC were moved to higher crustal levels along the footwall of the DSA normal ductile shear zone. The formation of F3 folds and final uplift of the TLMC (47-35 Ma) is postulated to be the consequence of transpression related to later Eocene dextral motion along the Yalakom fault The TLMC has structural style and timing of deformation similar to metamorphic core complexes in southeastern B.C. Local and regional evidence is consistent with the formation of the TLMC in a regional extensional setting within a vigorous magmatic arc. Science, Faculty of Earth, Ocean and Atmospheric Sciences, Department of Graduate

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Gallardo, Garcia Alejandro. "Middle Eocene-Early Miocene larger foraminifera from Dhofar (Oman) and Socotra Island (Yemen)." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/336096.

Testo completo

Abstract (sommario):

Here, the larger foraminifera found in Middle Eocene-Early Miocene rocks from Dhofar (Oman) and Socotra Island (Yemen) are studied in detail. The architectural analysis leads to the description of four new genera and nine new species: five agglutinated foraminifera, Pseudolituonella roberti n. sp., Socotraella ashawqi n. gen. n. sp., Pseudochrysalidina ayaki n. sp., Barattolites andhuri n. sp. and Dhofarella aydimi n. gen. n. sp.; and four porcellaneous foraminifera, Idalina grelaudae n. sp., Idalina pignattii n. sp., Macetadiscus incolumnatus n. gen. n. sp. and Omanodiscus tenuissimus n. gen. n. sp. The larger foraminifera identified in a Composite section located in Western Dhofar, in the Shuwaymiyah section located in Eastern Dhofar and in the Wadi Ayak section located on Socotra Island, has facilitated the identification of the following larger foraminifera zones: SBZ 14-SBZ 15 (Middle Lutetian), SBZ 16 (Late Lutetian), SBZ 17 (Bartonian), SBZ 18 (latest Bartonian-earliest Priabonian), SBZ 19-SBZ 20 (Priabonian), SB 21-SB 22A (Rupelian), SB 22B-SB 23 (Chattian) and SB 24 (Aquitanian). All these data permit stablished the age of the following lithostratigraphic units: Dammam Fm. Andhur Mb Early Lutetian?-Middle Lutetian age (SBZ 13?-SBZ 14 partim), Qara Mb Middle Lutetian (SBZ 14-SBZ 15), Uyun Mb Late Lutetian (SBZ 16). Aydim Fm. Heiron Mb Bartonian (SBZ 17), Moosak Mb upper Bartonian-Priabonian (SBZ 18-SBZ 20), Tagut Mb Priabonian (SBZ 19-SBZ 20), Haluf Mb Priabonian (SBZ 19-SBZ 20) till SBZ 21 on Socotra Island. Ashawq Fm Rupelian (SB 21-SB 22A). Mughsayl Fm Chattian-Aquitanian (SB 23-SB 24). En esta tesis se han estudiado en profundidad los macroforaminíferos encontrados en rocas del Eoceno Medio al Mioceno Inferior de la región del Dhofar (Sultanato de Omán) y de la isla de Socotra (Yemen). Su análisis arquitectural permite la descripción de cuatro géneros nuevos así como de nueve nuevas especies; cinco de macroforaminíferos aglutinados, Pseudolituonella roberti n. sp., Socotraella ashawqi n. gen. n. sp., Pseudochrysalidina ayaki n. sp., Barattolites andhuri n. sp. y Dhofarella aydimi n. gen. n. sp.; y cuatro de macroforaminíferos aporcelanados, Idalina grelaudae n. sp., Idalina pignattii n. sp., Macetadiscus incolumnatus n. gen. n. sp. y Omanodiscus tenuissimus n. gen. n. sp. Los macroforaminíferos identificados en la sección Compuesta, situada en el Dhofar Occidental; en la sección de Shuwaymiyah, situada en el Dhofar Oriental y en la sección de Wadi Ayak, localizada en la isla de Socotra, han facilitado la identificación de las siguientes biozonas de macroforaminíferos: SBZ 14-SBZ 15 (Luteciense Medio), SBZ 16 (Luteciense Superior), SBZ 17 (Bartoniense), SBZ 18 (Bartoniense Superior-Priaboniense Inferior), SBZ 19-SBZ 20 (Priaboniense), SB 21-SB 22A (Rupeliense), SB 22B-SB 23 (Catiense) and SB 24 (Aquitaniense). Todos estos datos permiten establecer la edad de las siguientes unidades litoestratigráficas; Formación Dammam: Miembro Andhur Mb Luteciense Inferior?-Luteciense Medio (SBZ 13? -SBZ 14 partim), Miembro Qara Luteciense Medio (SBZ 14-SBZ 15), Miembro Uyun Luteciense Superior (SBZ 16). Formación Aydim: Miembro Heiron Bartoniense (SBZ 17), Miembro Moosak Bartoniense Superior -Priaboniense (SBZ 18-SBZ 20), Miembro Tagut Priaboniense (SBZ 19-SBZ 20), Miembro Haluf Priaboniense (SBZ 19-SBZ 20) hasta SBZ 21 en la isla de Socotra. Formación Ashawq Rupeliense (SB 21 SB-22A). Formación Mughsayl Catiense-Aquitaniense (SB 23 SB-24).

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Gupta, K. D. "Tectono-stratigraphic evolution of deep-marine clastic systems in the Eocene Ainsa and Jaca basins, Spanish Pyrenees : petrographic and geochemical constraints." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1445277/.

Testo completo

Abstract (sommario):

The Early-Middle Eocene deep-marine siliciclastic systems of the Ainsa and Jaca foreland basins, Spanish Pyrenees, have been used to develop and support generic models for deep-marine deposits, from process-based to system-based perspectives, and these ideas have been applied globally by academics and industry alike. Despite the considerable amount of research into many aspects of sedimentology of the Ainsa and Jaca basins, the widely-adopted stratigraphic correlation of sandstone systems in the Ainsa and Jaca basins is very poorly-constrained, although the stratigraphy and accurate correlation of sandstone bodies along the basin are paramount to any depositional models that arise from any studies in the Ainsa and Jaca basins. This study used petrography, geochronology, major and trace element geochemistry to better constrain and understand the evolution of the basinal sediments and fingerprint the sandstone bodies within the Ainsa-Jaca basin as a means of correlation. An additional pilot study was carried out on carbon and oxygen isotopic signatures of larger foraminifera from the outcrops. Three discrete sediment sources are recognised for the deep-marine Early to Mid-Eocene sandstone bodies in the Ainsa and Jaca basins. The arenite composition in the Ainsa and Jaca basins is interpreted to be mainly controlled by synsedimentary tectonic processes that led to changes in sediment sources during basin evolution. Comprehensive petrography data shows that each system of the Ainsa and Jaca basins has a characteristic petrofacies. Three main petrofacies are recognised and on the basis of these petrofacies, a revised correlation of the sandy systems is proposed between the more proximal Ainsa basin, and the more distal Jaca basin sediments, now separated by the Boltana anticline, across which it is impossible to actually trace out individual beds or sandstone packages between both basins. The new correlation scheme, along with the newly identified sediment provenances, changes the current (published) understanding of the Ainsa and Jaca basins evolution and palaeogeography.

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Geyikcioglu, Erbas Bedia. "Meter Scale Cycles In The Eocene Cayraz Formation (haymana Basin) And Response Of Foraminifers To Cyclicity." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/2/12610161/index.pdf.

Testo completo

Abstract (sommario):

The aim of this study is to investigate the nature of the meter-scale cycles in the &Ccedil ayraz Formation of the Middle Eocene age and to study the response of foraminifera to the sedimentary cyclicity. In order to perform this study, two stratigraphic sections, which are 44,55 m and 25,95 m in thickness, were measured on a regularly bedded succession mainly composed of carbonates and siliciclastics in the &Ccedil ayraz Formation of the Haymana Basin. In this study, detailed microfacies analyses were carried out in the studied sections and 10 different microfacies types were identified strictly based on the biofacies in order to define meter scale cyclic sedimentation. Based on the detailed microfacies analysis and the distribution of the vertical facies relationships a composite depositional model is suggested. According to this model, three major facies associations were distinguished, from deepest to shallowest, as: shallow open marine, shoal and lagoon. Studied sections are composed of meter-scale cycles of both upward shoaling or deepening in character and based on the stacking pattern of meterscale cycles two systems tracts were identified along the measured sections. Section 1 is represented by highstand systems tract (HST) and section 2 is represented by lowstand systems tract (TST). In this study, the responses of benthic foraminiferal groups to the sedimentary cyclicity have been documented by quantitative and statistical analysis to understand the shallowing upward cycles, which are fundamental stratigraphic units, in the &Ccedil ayraz Formation of Middle Eocene age. Among foraminifera, particularly the forms like Nummulites, Assilina and Discocyclina are excellent in order to detect cyclic variations of facies. These studies lead to understand shoaling-upward character of the meter-scale cycles, which are the building blocks of the &Ccedil ayraz Formation.

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Scotchman, J. I. "Stratigraphic context and timing of sand supply to deep-marine Ainsa-Jaca basin, middle Eocene, Spanish Pyrenees : constraints from geochemistry and sedimentology." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1347242/.

Testo completo

Abstract (sommario):

The sediment flux to a basin is controlled by a complex combination of tectonics, climatic variability and stochastic events, thereby creating a cryptic geological record. Deconvolving the effects of individual factors controlling sedimentation can often be challenging, due to a variety of reasons including a lack of outcrop, a poor understanding of the regional tectonic framework and insufficiently detailed geological maps. However, many of these deficiencies can be overcome within the deep-marine Ainsa basin, South Central Pyrenees where detailed research over the last decade has provided an extensive knowledge base. The Ainsa basin comprises ~4 km of middle Eocene deep-marine sediments. Basin stratigraphy consists of a succession of ~25 discrete sandy submarine fans and inter-fan deposits belonging to the Hecho Group. Recently it has been hypothesised that the supply of coarse-clastic sediment to the basin was paced by orbitally induced climate and/or sea level variability, whilst tectonics controlled the locus of deposition. This hypothesis is tested within the Upper Hecho Group using a refined basin age model and the creation of floating orbital time scales between submarine fans. Using calcareous nannofossil and large shallow benthic foraminifera, deposition of the Upper Hecho Group took place over a 6.0-8.3 Myr period between ~40.5-48.4 Ma, giving an average sediment accumulation rate (SAR) of 43.2±10.5 cm/kyr. Stratigraphic time series analyses of inter-fan fine-grained sediments indicate the presence of short eccentricity, obliquity and precession Milankovitch cycles. These floating time scales provide average SARs of 36, 28 and 25-33 cm/kyr for the Banaston, Ainsa and Guaso systems respectively. Applying these age models to the three systems suggest that submarine fan deposition potentially corresponds to specific eccentricity minima. As in the Pleistocene, such Milankovitch forcing could be linked with ephemeral glacio-eustatic low-stand conditions, associated with increased coarse sediment flux to the deep-marine Ainsa basin.

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Hourdebaigt, Marie-Laure. "Stratigraphie et sedimentologie des molasses synorogeniques en bearn et en bigorre." Toulouse 3, 1988. http://www.theses.fr/1988TOU30187.

Testo completo

Abstract (sommario):

Etude des molasses continentales proximales affleurant au-dessus des terrains nummulitiques en bearn et en bigorre. Dans le bassin au sud de pau, l'etude geometrique et sedimentologique permet de distinguer deux formations conglomeratiques: les poudingues inferieur et superieur, separes par une discordance. Le passage de l'un a l'autre est marque par un changement de la petrographie, de la granulometrie et de la morphometrie des galets. Ils sont attribues a l'eocene et rattaches respectivement a la 1ere et 2eme unite du poudingue de palasson. Dans le secteur occidental, les molasses conglomeratiques s'organisent en discordance progressive et sont rattachees au ludien. Elles sont correlees avec la 3eme unite du poudingue de palasson. Dans le secteur bigourdan, les 3 unites du poudingue de palasson ont ete retrouvees

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Edgar, Kirsty M. "Palaeoclimatology, stratigraphy and biotic responses in the middle Eocene." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/65670/.

Testo completo

Abstract (sommario):

The Middle Eocene (37 to 49 million years ago, Ma) was characterised by warmer global temperatures and higher atmospheric carbon dioxide (pCO2) levels than today with only small/non-existant icesheets. Because predicted pCO2 levels for the coming century have not been seen on Earth since at least ~40 Ma thus, the primary objective of this thesis is to improve our understanding of the nature, timing and consequences of carbon perturbations in the Middle Eocene between 39 and 43 Ma. In Chapter 3, a new (instrument specific) methodology for measuring Mg/Ca in foraminiferal calcite is developed to enable the simultaneous measurement of additional trace elements indicative of foraminiferal test contamination. This new methodology enables Mg/Ca data to be screened more efficiently for contamination and increases confidence in palaeoceanographic reconstructions based on the Mg/Ca palaeotemperature proxy. In Chapter 4, new foraminiferal stable isotope records (~5 kyr resolution) from Demerara Rise in the equatorial Atlantic are generated to test the hypothesis that the onset of continental ice sheets in the Northern Hemisphere occurred at ~41.6 Ma in the Middle Eocene, 30 million years earlier than previously thought. The new data herein, indicate that if continental ice sheets were present, they were small and easily accommodated on Antarctica with no need to invoke storage of ice in the Northern Hemisphere. The dearth of appropriate Middle Eocene sedimentary sections on which to work means that a well calibrated timescale for this interval remains to be produced. In Chapters 5 and 6, this problem is addressed using Middle Eocene sediments recovered from the Blake Nose plateau in the western North Atlantic. A new high resolution magnetic stratigraphy and new quantitative foraminiferal biostratigraphic counts were developed between 39.5 and 42.0 Ma, which allows re-assessment and refinement of previous magnetostratigraphic and biostratigraphic interpretations. This provides excellent age control for these sediments and new calibrations to the Geomagnetic Polarity Time Scale (GPTS). In Chapter 7, the first high-resolution quantitative planktic foraminiferal assemblage counts were developed for the global warming event the Middle Eocene Climatic Optimum (MECO) between ~39.5 and 41.5 Ma. New biotic records show that the MECO was accompanied by significant biotic shifts that suggest a shift from warm, oligotrophic surface waters to warmer, more productive surface waters during the MECO.

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Chandler, Matthew R. "The Provenance of Eocene Tuff Beds in the Fossil Butte Member of the Green River Formation of Wyoming: Relation to the Absaroka and Challis Volcanic Fields." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1517.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

26

Sanjuan, i. Girbau Josep. "Els caròfits del límit Eocè-Oligocè de la Conca de l’Ebre." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/133718.

Testo completo

Abstract (sommario):

Aquesta tesi doctoral té com a objectiu principal la caracterització taxonòmica, paleoecològica, paleobiogeogràfica i biostratigràfica dels caròfits de l’Eocè superior-Oligocè inferior de la Conca de l’Ebre. La flora de caròfits de l’Eocè superior-Oligocè inferior del marge est de la Conca de l’Ebre està constituïda per Sphaerochara labellata, Chara aff. antennata, C. artesica n. sp., C. rhenana, C.microcera, Psilochara aff. acuta, Lamprothamnium sp., Gyrogona caelata, Nodosochara jorbae, Lychnothamnus longus, L. stockmansii, L. grambastii, L. vectensis, L. pinguis (=L. major), Nitellopsis (Tectochara) merianii, Harrisichara lineata, H. vasiformis-tuberculata i H. tuberculata. En totes es caracteritza el polimorfisme intraespecífic a parti d’un estudi biomètric dels girogonits. Des d’un punt de vista taxonòmic se sinonimitzen, a partir de les poblacions tipus, dues espècies clau en biostratigrafia del límit Eocè-Oligocè europeu, Lychnothamnus pinguis i L. major. L’anàlisi paleoecològica de les associacions de caròfits de l’Eocè superior al sector NE de la conca de l’Ebre ha permés determinar que espècies clau per la biostratigrafia del límit Eocè-Oligocè presenten clares limitacions paleoecològiques. Així, Harrisichara vasiformis-tuberculata creixeria només en ambients salabrosos i soms pròxims a la costa, Harrisichara lineata es relaciona amb llacs soms d’aigua dolça i Harrisichara tuberculata abunda, però no és exclusiva, de llacs perennes i profunds d’aigua dolça. Altres espècies com Sphaerochara labellata, Lychnothamnus stockmansii, L. pinguis (=L. major) i Chara microcera es troben en llacs permanents. En conclusió, la presència o absència d’aquestes espècies, i per tant, de les biozones homònimes en una determinada conca europea depèn del tipus de fàcies i del paleoambient associat mes que no d’esdeveniments evolutius. Altres espècies com Lychnothamnus vectensis, Nodosochara jorbae, Lychnothamnus longus o Chara artesica n. sp., en canvi, no presenten cap limitació ecològica important dins el context dels sistemes aquàtics continentals. L’anàlisi paleobiogeogràfica de la caroflora de l’Eocè superior-Oligocè inferior d’Europa permet identificar una polaritat latitudinal en la distribució i abundància de les espècies. No obstant, partint de les espècies comunes a totes les conques europees es defineix una bioprovíncia europea per l’Eocè superior-Oligocè inferior la qual es pot caracteritzar a partir dels llinatges Harrisichara vasiformis-H. tuberculata i Lychnothamnus stockmansii-L. major així com de les espècies Nitellopsis (T.) merianii i Chara microcera. Les variacions regionals d’aquesta flora responen a factors climàtics locals i a factors ecològics lligats a la dinàmica de cada conca. La distribució biogeogràfica de determinades espècies, com Sphaerochara labellata o L. pinguis ha mostrat que l’us d’aquestes especies en biostratigrafia està condicionada per factors paleogeogràfics. L’anàlisi de la biogeografia històrica del llinatges evolutius Lychnothamnus stockmansii-L. major i Nitellopsis(Tectochara)merianii-N. obtusa suggereix que les espècies de caràcies fòssils seguien diferents patrons de dispersió en funció de la disposició dels seus gametangis (dioica vs. monoica). És clar que les espècies monoiques com Lychnothamnus stockmansii-L. major, amb velocitats d’expansió geològicament instantànies, són idònies alhora de correlacionar biostratigraficament conques allunyades. Des d’un punt de vista biostratigràfic, les associacions de caròfits han permès precisar l’atribució biostratigràfica de les unitats litostratigràfiques estudiades. S’ha proposat una biozonació de carofits per la conca de l’Ebre a partir d’espècies ecològicament euritípiques. Aquesta biozonació s’ha correlacionat amb la biozonació local de vertebrats i s’ha calibrat amb la magnetostratigrafia definida a l’est de la conca per Barberà et al. (2001) i Costa et al. (2010, 2011). La nova proposta permet caracteritzar el límit Eocè-Oligocè dins la biozona de Lychnothamnus vectensis. A més, s’ha revisat la biozonació europea avui dia en us. La calibració dels límits de les biozones europees amb l’escala del temps absolut mitjançant la magnetostratigrafia ha permès, per primera vegada, precisar la durada temporal de les biozones de caròfits del límit Eocè-Oligocè.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Moss, Graham. "The Port Willunga Formation : Eocene/Oligocene boundary stratigraphy and foraminiferal turnover /." Adelaide, 1989. http://web4.library.adelaide.edu.au/theses/09SB/09sbm913.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

28

King, Christopher. "Stratigraphy of the London Clay Formation (Early Eocene) in the Hampshire Basin." Thesis, Kingston University, 1991. http://eprints.kingston.ac.uk/20552/.

Testo completo

Abstract (sommario):

Stratigraphy of the London Clay Formation (Early Eocene) in the Hampshire Basin Lithological logging and micropalaeontological analysis of selected exposures and boreholes in the London Clay Formation of the Hampshire Basin has enabled detailed correlation and subdivision of the Formation. The sediments are classified into nine main lithofacies, deposited in marine shelf and marginal-marine environments. The recognition and correlation of numerous minor stratigraphic discontinuities within the Formation enables its subdivision into 22 depositional sequences. Within each sequence, an initial marine-flooding transgressive episode characterised by glauconitic sediments is followed by progradation of shallow marine and marginal marine facies from the basin margin. Cross-stratified sands with basal erosional contacts at the top of some sequences record rapid sea-level falls, with channelling of the shelf. The depositional sequences within the London Clay Formation are mainly fourth order parasequences, and are interpreted as induced by eustatic sealevel fluctuations. The detailed stratigraphic record is used to produce a coastal on1ap curve for the time-interval covered by the London Clay Formation. 85 species of benthonic foraminiferids and 79 species of ostracods are recorded from the London Clay Formation. Their taxonomy is summarised. Other microfossil groups including calcareous 'microproblematica', planktonic foraminiferids, diatoms, serpulids and bryozoa have also been studied. The biostratigraphic significance of all these groups is assessed, and selected biostratigraphic events are utilised for correlation within the Hampshire Basin. Correlation with other areas in North West Europe is discussed. The biostratigraphic and magnetostratigraphic data is summarised in order to attempt placement of the London Clay Formation within the standard geochronological scale. The palaeogeographical context of the Hampshire Basin during the Early Eocene is assessed.

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Petit, Lisiane. "Le gisement de vertebres continentaux de fontliasmes (eocene superieur du poitou) : stratigraphie, sedimentologie, paleontologie." Poitiers, 1987. http://www.theses.fr/1987POIT2119.

Testo completo

Abstract (sommario):

On etudie la faune de vertebres continentaux livree par les sables et argiles marbres de fontliasmes, poitou. Le degre d'evolution de la faune permet d'attribuer un age auversien aux depots. Les caracteristiques sedimentologiques et fauniques montrent le passage dans le temps d'un regime fluviatile a un regime lacustre; le milieu est marecageux, boise, soumis a un climat tropical humide. La presence du crocodilien allognathosuchus haupti atteste de l'existence d'echanges fauniques entre l'europe et l'amerique du nord a l'eocene moyen

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Hanif, Muhammad. "Stratigraphy and Palaeoenvironment of the Paleocene/Eocene boundary interval in the Indus Basin, Pakistan." Thesis, University of Plymouth, 2011. http://hdl.handle.net/10026.1/865.

Testo completo

Abstract (sommario):

Marine sedimentary sections across the Paleocene/Eocene (P/E) boundary interval are preserved in the Patala Formation (Upper Indus Basin) and Dungan Formation (Lower Indus Basin), Pakistan. The P/E interval of the Patala Formation is composed of limestone and shale inter-beds indicating deposition on a carbonate platform. The analysis of larger foraminifera across the P/E interval from the Patala Formation (Kala Chitta Ranges), allows the recognition of the Larger Foraminiferal Turnover (LFT). The Larger Foraminiferal Turnover (LFT) observed in the Patala Formation is associated with the PETM (Paleocene Eocene Thermal Maximum) global climatic event and allows the recognition of the P/E boundary in shallow water carbonates of the Indus Basin. This turnover is already reported from other Tethyan sections and from the Salt Range (Upper Indus Basin), Pakistan. The recognition of the LFT allows the inter-basinal and intra-basinal correlation of the P/E interval of the shallow carbonates of the Indus Basin, Pakistan. The available literature on the Paleocene-Eocene Patala and Dungan formations is used to review the planktonic foraminiferal biostratigraphy of the P/E interval. The planktonic foraminiferal zones in the P/E interval of the Indus Basin are identified and reviewed in the light of new international zonations. The planktonic foraminiferal content of the Dungan Formation allows its correlation with the Laki Formation of Rajesthan (India). Four dinoflagellate zones in the P/E interval of the Rakhi Nala section (Lower Indus Basin) are identified and correlated with international and regional zonations. The quantitative analysis of the dinoflagellate cyst assemblages together with geochemical data (i.e., carbon isotopes (organic only), C/N ratio, TOC, carbonate content) is used to reconstruct the palaeoenivronment across the P/E interval. The dinocyst assemblages in general, and the abundance of Apectodinium spp. in particular, indicate the warmer surface water conditions of the global PETM event. The dinocyst assemblages allow the local correlation of the Dungan Formation (part) of the Sulaiman Range with the Patala Formation (part) of the Upper Indus Basin and global correlation of the Zone Pak-DV with the Apectodinium acme Zone of the Northern and Southern hemispheres. The carbon isotopic excursion (CIE) associated with PETM is now globally used to identify the P/E boundary. The CIE in total organic carbon (i.e., δ13CTOC = -28.9‰) and total fine fraction organics (i.e., δ13CFF= 26.4‰) from the Indus Basin is reported for the first time. This CIE record from the Indus Basin is compared with other Tethyan sections from Egypt and Uzbekistan and is also compared with the global sections from USA (Northern hemisphere) and from New Zealand (Southern hemisphere).

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Simmons, Adam Thomas. "Magmatic and hydrothermal stratigraphy of Paleocene and Eocene porphyry Cu-Mo deposits in southern Peru." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45533.

Testo completo

Abstract (sommario):

A geological investigation of the of the Paleocene-Eocene Cu-Mo porphyry belt of southern Peru was undertaken at the Quellaveco Cu-Mo porphyry system with complimentary work completed at the Cuajone and Toquepala mines. This work adds to the understanding of the formation and evolution of igneous systems associated with Cu-Mo porphyry formation in an understudied but economically significant copper source globally. The Quellaveco Igneous Complex is composed of at least five phases of porphyritic intrusions which were emplaced into a slightly older equigranular granodiorite batholith and Late Cretaceous Toquepala Group volcanic rocks. These intrusions were emplaced from approximately 58Ma to 53Ma. The intrusions with the closest temporal and spatial association to copper may have been emplaced in as short a timespan as approximately 1.5m.y. These time periods and time spans are almost identical to those for the emplacement of the igneous systems at Cuajone and Toquepala. At Quellaveco, zircon mineral chemistry indicates that the igneous systems associated with porphyry copper formation are different to those not associated with porphyry copper formation. Geochemical disruptions, flat to cup shaped Eu/Eu* anomalies and rapid changes in temperature of formation of the zircons with their growth are indicative of zircons from the porphyry intrusions from Quellaveco. It is postulated that these geochemical signatures may indicate that intrusions associated with the formation of the hydrothermal systems are derived from fractionating and cooling magmatic systems which remained relatively oxidized and were subject to periodic geochemical disturbance. The geochemical disturbances may reflect a dynamic deeper magmatic system where magma mixing, replenishment and scouring of wall rock took place. At Quellaveco, each of the porphyritic intrusions are temporally related with a hydrothermal system. Each hydrothermal system is an evolution of mineral assemblages in veins from biotite-magnetite-chalcopyrite rich veins to quartz-sulphide rich veins to quartz vein with quartz-sericite selvages. This sequence of vein evolution repeats itself at Quellaveco at least four times. Each hydrothermal system occurs immediately after the emplacement of at least five porphyry intrusion suites.

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Poyatos-Moré, Miquel. "Physical stratigraphy and facies analysis of the castissent tecto-sedimentary unit." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/145397.

Testo completo

Abstract (sommario):

L’anàlisi de la sedimentologia, geometria i trajectòria de diverses clinoformes deltaiques successives en estudis d'aflorament o en bases de dades de sísmica de reflexió han estat àmpliament utilitzats com una eina per a (1) inferir canvis en el nivell del mar i per a (2) interpretar els factors de control a curt i llarg termini sobre la evolució dels marges de conca, així com en la durada i tipus de transport de sediment groller des dels continents fins als oceans. Els models deposicionals, majoritàriament enfocats en la influència de l’eustatisme (acomodació) i l‘aport de sediment, principalment a partir de dades sísmiques de gran escala, mostren un menor interès/focus en l’anàlisi de fàcies i els procesos deposicionals que s’en infereixen, els quals operen en diferents posicions al llarg dels clinotemes individuals, i en l’estudi de com aquests procesos canvien amb la trajectòria i el temps. Les seqüències deposicionals de Castissent, de l’Eocè inferior (alogrup de Castissent, Pirineus sud-centrals, Espanya) consisteixen principalment, a la conca d’Ainsa, en dipòsits de barra de desembocadura i lòbuls sorrencs de front deltaic en transició a turbidites de talús, formats en un sistema de river-delta dominat per avingudes. La deposició d’aquests cossos sedimentaris va estar fortament controlada per la interacció entre fluxos hiperpícnics d’origen continental, la influència dels processos litorals sobre aquests fluxos, i l’activitat tectònica, tant local com regional, la cinemàtica sinsedimentària de la qual encara no ha estat explicada en suficient detall. La cartografia i correlació de cicles sedimentaris d’alta freqüència evidencia que aquests poden ser considerats clinotemes deltaics limitats per les seves relatives superfícies límit o clinoformes (discordances sigmoïdals), la formació de les quals estaria estrictament controlada per l’activitat tectònica. Per altra banda, els perfils sísmics d’alta resolució vinculats a dades de pou i sondejos proporcionen els mitjans necessaris per a lligar l’arquitectura deposicional (trajectòria de clinoformes) amb els processos i patrons de dispersió de sediment. L’Expedició 313 de l’IODP (Integrated Ocean Drilling Program) va perforar un grup de clinotemes del Miocè a l’offshore de Nova Jersey per tal de capturar un registre complet de varacions del nivell del mar a través de la integració d’estratigrafia sísmica, dades de pou i sondejos, i cronostratigrafia. En la base de dades de l’Expedició 313, aquesta valoració es pot efectuar a través de diferents clinotemes successius, amb els respectius anàlisis de facies i interpretacions de processos i ambients deposicionals al llarg d’un mateix clinotema (Poyatos-Moré and Hodgson, 2012; Hodgson et al., in prep.). No obstant, estudis d’aflorament com el de les seqüències de Castissent o de subsòl com el de Nova Jersey tracten sovint l’acomodació i l’aport sedimentari com un problema bidimensional, mitjancant l’anàlisi d’un perfil de marge de conca paral·lel a la direcció principal de l’aport. Els resultats d’aquests estudis han estat comparats amb la part inferior de la Formació Waterford (Conca de Karoo, Sud-àfrica), un cas d’estudi d’aflorament tridimensional d’un sistema de talús-plataforma exhumat, que permet la identificació de la posició del rollover de la clinoforma i de les associacions de fàcies al llarg de tres perfils deposicionals paral·lels a l’aport (Jones, 2013; Jones et al., 2013a and b). Aquests perfils de marge de conca de la Fm Waterford mostren tots ells trajectòries similars, tot i que amb una significativa variabilitat lateral pel que fa a la presencia de sorra al talús. D’aquesta manera, aquest estudi demostra que la variabilitat lateral en la fisiografia dels marges de conca afecta significativament a la dispersió de sediment entre ambients de plataforma, talús i fons de conca, i ha de ser per tant considerada, juntament amb el règim de processos, com a factor de control clau quan s’intenten elaborar prediccions de bypass de sediment en successions de marge de plataforma. The analysis of sedimentology, geometry and trajectory of successive deltaic clinoforms in outcrop-based studies or in high-resolution reflection seismic datasets has been widely employed as a tool to (1) infer relative sea-level changes and (2) to interpret short and long-term factors controlling basin margin evolution and timing of coarse-grained sediment delivery from continents to oceans. Sea-level (accommodation) and sediment supply-driven models have been developed mainly on large-scale seismic data, with less focus on sedimentary facies analysis and inferred depositional processes in operation at different positions along individual clinothems, and how these process change with trajectory and time. The Lower Eocene Castissent depositional sequences (Castissent Group, South-Central Pyrenees, Spain) mainly consist, in the Ainsa basin, in mouth-bar deposits and delta front sandstone lobes in transition to slope turbidites, deposited in a flood-dominated river-delta system. Deposition of these bodies was strongly controlled by the interaction between continental-derived hyperpycnal flows, the influence of shoreline processes over these flows and the local and regional tectonic activity, whose syn-sedimentary thrust-and-fold kinematics has not been explained in enough detail yet. Field mapping and correlation of high-frequency cycles show that they can be considered deltaic clinothems bounded by clinoform surfaces (their sigmoid bounding unconformities) whose formation is strictly controlled by tectonics. Moreover, high resolution seismic profiles tied to cored and dated boreholes data provide a means to link the depositional architecture (clinoform trajectory) to sediment dispersal processes and patterns. IODP Expedition 313 cored a set of Miocene clinothems offshore New Jersey to capture a complete record of sea-level change through integration of seismic stratigraphy, core and well logs, and chonostratigraphy. In the Expedition 313 dataset, this analysis can be performed over successive clinothems, with the assessment of sedimentary facies and process-based interpretations of environments of deposition down a single clinothem (Poyatos-Moré and Hodgson, 2012; Hodgson et al., in prep.). However, some outcrop-based studies like the Castissent sequences or subsurface-based studies like the New Jersey margin commonly treat accommodation and sediment supply as a 2D problem, by analyzing a margin profile parallel to the main sediment route. The results of these works have been compared with the lower Waterford Formation (Karoo basin, South-Africa), which provides a 3D outcrop-based case study of an exhumed shelf-to-slope system that allows the identification of clinoform rollover positions and depositional facies associations along three depositional dip profiles (Jones, 2013; Jones et al., 2013a and b). These parallel basin margin profiles of the lower Waterford Formation show all broadly similar trajectories, although with a significant along-margin variability. Thus, strike variability in basin margin physiography strongly affects sediment dispersal between shelf, slope and basin floor settings and it must be therefore considered together with process regime as a key controlling factor when attempting stratigraphic predictions of sediment bypass in shelf-margin successions.

Gli stili APA, Harvard, Vancouver, ISO e altri

33

Rancan, Cristiano Camelo. "Estratigrafia da série eoceno no Baixo do Mosqueiro, bacia de Sergipe-Alagoas /." Rio Claro, 2017. http://hdl.handle.net/11449/151380.

Testo completo

Abstract (sommario):

Orientador: Rosemarie Rohn Davies Coorientador: Wagner Souza-Lima Banca: Norberto Morales Banca: Claudio Borba Resumo: As rochas do Grupo Piaçabuçu foram alvo de poços exploratórios nos últimos dez anos, nas águas profundas a ultra-profundas da Bacia de Sergipe-Alagoas, que lograram êxito na prospecção de hidrocarbonetos. São também um clássico na história do petróleo no Brasil, pois nelas estão os primeiros campos de produção em águas oceânicas, em reservatórios paleogenos do compartimento estrutural Baixo do Mosqueiro. O estudo estratigráfico da Série Eoceno, com base em perfis elétricos e biozoneamento de poços situados no Baixo do Mosqueiro, exigiu o zoneamento do Grupo Piaçabuçu como um todo, dividido nos intervalos Senoniano, Paleoceno, Eoceno e Oligo-Neogeno. O depocentro senoniano situa-se na Depressão de Areia Branca e os demais na Depressão de Vaza-Barris, deslocados ao longo de cada intervalo, com migração gradual para S e W. A Série Eoceno foi dividida nos intervalos Inferior, Médio e Superior. O primeiro tem depocentro na Depressão de Dourado e os demais na Depressão de Vaza-Barris, condicionados por halocinese e deformação no embasamento. A deposição do Eoceno Inferior ocorreu como uma continuidade do evento de afogamento que se estendia desde o Neopaleoceno (pontuado por deposição progradacional de mar baixo), com superfície de máxima inundação ao nível da biozona N-420. Esta seção possivelmente aflora em superfície na Depressão da Ilha de Mem de Sá. A discordância que define a base do Eoceno Médio (Discordância Pré-luteciana) representa o principal evento erosivo de toda a série e a partir dela os sistemas progradaram no Meso e Neoeoceno, com recuo de depocentro no último. No Mesoeoceno o limite entre o Baixo do Mosqueiro e a Plataforma de Estância foi colmatado pela sedimentação e as sub-bacias de Sergipe e Jacuípe passaram a atuar como um único compartimento estrutural. Na Depressão de Vaza-Barris predominaram ... (Resumo completo, clicar acesso eletrônico abaixo) Abstract: Piaçabuçu Group rocks were exploratory targets of many wildcats along the last ten years, on deep to ultradeep water of Sergipe-Alagoas Basin, with sucess in petroleum search. This stratigraphic unit is a classic production zone on Brazil's petroleum history, because the first offshore discovery where there, in Paleogene reservoirs of Mosqueiro Low Compartiment. A stratigraphic study in Eoceno Series, based on well logs and biostratigraphic data had the objective of understand depositional systems spacial distribution, response to accomodation space variation, controlled by eustasy and deformational history in time. In order to compreend this, Piaçabuçu Group was zoned in four intervals: Senonian, Paleocene, Eocene and Oligo-Neogen. Senonian Depocenter was in Areia Branca Trough and for the others in Vaza-Barris Trough, but gradually migrated along time to S and W. Eocene Series was shared in tree intervals: Lower, Middle and Upper. Lower Eocene has depocenter on Dourado Trough, while Middle and Upper Eocene are in Vaza-Barris Trough, controlled by halokinesys and basement deformation, respectively. Lower Eocene deposition was a continuity of Upper Palocene drowning interval (puncuated by progradational deposition on lowstand), with maximum flooding surface at N-420 biozone level. This interval probably outcrops at Ilha de Mem de Sá Trough, in western offshore sector. Middle Eocene basal unconformity is the main erosive event of the Series, and from it, depositional systems are strongly progradacional during Middle and Upper Eocene, with backstepping on the last one. During Lutetian and Bartonian, limits between Mosqueiro Low and Vaza-Barris Trough were buried ans Segipe and Jacuípe sub-basins turned to a single structural compartiment. In VazaBarris Trough, gravity sediments flow facies associations were more commom while in eastern troughs and steps, delta ... (Complete abstract electronic access below) Mestre

Gli stili APA, Harvard, Vancouver, ISO e altri

34

Hansman, Reuben J., Uwe Ring, Stuart N. Thomson, Brok Bas den, and Konstanze Stübner. "Late Eocene Uplift of the Al Hajar Mountains, Oman, Supported by Stratigraphy and Low-Temperature Thermochronology." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/627072.

Testo completo

Abstract (sommario):

Uplift of the Al Hajar Mountains in Oman has been related to either Late Cretaceous ophiolite obduction or the Neogene Zagros collision. To test these hypotheses, the cooling of the central Al Hajar Mountains is constrained by 10 apatite (U-Th)/He (AHe), 15 fission track (AFT), and four zircon (U-Th)/He (ZHe) sample ages. These data show differential cooling between the two major structural culminations of the mountains. In the 3km high Jabal Akhdar culmination AHe single-grain ages range between 392 Ma and 101 Ma (2 sigma errors), AFT ages range from 518 Ma to 324 Ma, and ZHe single-grain ages range from 62 +/- 3Ma to 39 +/- 2 Ma. In the 2 km high Saih Hatat culmination AHe ages range from 26 +/- 4 to 12 +/- 4 Ma, AFT ages from 73 +/- 19Ma to 57 +/- 8 Ma, and ZHe single-grain ages from 81 +/- 4 Ma to 58 +/- 3 Ma. Thermal modeling demonstrates that cooling associated with uplift and erosion initiated at 40 Ma, indicating that uplift occurred 30 Myr after ophiolite obduction and at least 10 Myr before the Zagros collision. Therefore, this uplift cannot be related to either event. We propose that crustal thickening supporting the topography of the Al Hajar Mountains was caused by a slowdown of Makran subduction and that north Oman took up the residual fraction of N-S convergence between Arabia and Eurasia.

Gli stili APA, Harvard, Vancouver, ISO e altri

35

Laurie, Ewan Robert. "Cyclostratigraphy and sequence stratigraphy of the Solent Group (Eocene-Oligocene) of the Isle of Wight, UK." Thesis, University of Greenwich, 2006. http://gala.gre.ac.uk/6217/.

Testo completo

Abstract (sommario):

A stratigraphic reinterpretation of the Eocene-Oligocene Solent Group is presented here, based on the Whitecliff Bay section of the Isle of Wight, Hampshire Basin, UK. High resolution palaeontological, sedimentologica and mineralogical analyses allow the establishment of facies groups, which are used to demonstrate the presence of seven conspicuous sequences. For the first time, these are tied to an accurate magnetostratigraphic framework. Investigation of the cyclic signal in clay mineralogical data reveals that sea level was controlled by the ~400ka cycle of astronomical (Milankovitch) forcing at this critical period in Earth history, when the change from a greenhouse world to an icehouse world took place. This has also allowed uncertainty surrounding the location of the Eocene-Oligocene boundary within the Solent Group to be cleared up. A major incision event associated with glacial build up at the Eocene-Oligocene boundary is recorded, but is smaller than that predicted by isotope records (Miller et al. 1991), possibly as a result of rapid subsidence rates.

Gli stili APA, Harvard, Vancouver, ISO e altri

36

Byrne, Monica C. (Monica Catherine). "A stable isotope stratigraphy for the Axel Heiberg Fossil Forest and its application to Eocene climate." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33941.

Testo completo

Abstract (sommario):

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2005. Includes bibliographical references (leaves 96-107). The Eocene era was a warm, climatically dynamic transitional period between the Paleocene greenhouse world and the Oligocene icehouse world. This study details carbon and hydrogen isotopic and biomarker analyses of samples of lignite (bulk fossil leaves), wood, paleosol, and resinite from the Middle to Late Eocene age fossil forest stratigraphy on Axel Heiberg Island, Nunavut, Canada. Bulk carbon isotopes show a record of frequent, large fluctuations on the scale of the Paleocene-Eocene Thermal Maximum benthic carbon excursion of [approx.] 2.6%₀ (Zachos 1999). However, terrestrial flora are less sensitive to CO₂ fluctuations given their capacity to regulate stomatal intake and the comparatively easy diffusion of CO₂ in air. Resinites (-22.8 +/- 1.7%₀) are enriched relative to bulk lignite (-24.7 +/- 0.75%₀), and wood (-21.66 +/- 0.45%₀) is also enriched relative to bulk lignite. Both 1) a scenario of periodic methane hydrate pulses and 2) a scenario of fluctuating forest stand LAI (leaf area index) are not inconsistent with our data. Either mechanism could be responsible for large carbon isotope shifts. Higher plant input dominated the n-alkane signature. Compound-specific hydrogen isotopes in n-alkanes show a record of marked secular change, with isotopes becoming generally lighter over the time span of the stratigraphy, though punctuated by singular fluctuations as large as 32%₀. (cont.) Polycyclic isoprenoid lipids (-266%₀ to -375%₀, mean 300%₀ +/- 38%₀) are characteristically depleted relative to n-alkanes (-238%₀ to -295%₀, mean -268%₀ +/- 10%₀). From the n-alkanes, we estimate that environmental water in the Eocene on Axel Heiberg Island was depleted -150%o +/- 24.8%o, which agrees with an estimate derived from cellulose, [delta]D-environmental = -133%₀ (Jahren 2003). (For comparison, modern precipitation at the site has a [delta]D value of [approx.] -213%₀, though precipitation should not be considered equivalent to environmental water.) This datum is consistent with a meridional weather patterns that may have carried moisture over continents towards high latitudes in the absence of a polar front, isotopically depleting precipitation to a greater extent than occurs today. However, seasonality cannot be discounted as a mechanism, given that colder temperatures would lead to colder condensation temperatures and thus, isotopically lighter precipitation. Monica C. Byrne. S.M.

Gli stili APA, Harvard, Vancouver, ISO e altri

37

Schuetz, Corinna. "Stratigraphy, petrography and geochemistry of the Kaiwhata Limestone, Pahaoa, New Zealand." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/232515/1/Corinna_Schuetz_Thesis.pdf.

Testo completo

Abstract (sommario):

This thesis examined the stratigraphy, petrography, and geochemistry of the Paleocene to Eocene pelagic sedimentary deposits in Pahaoa, Wairarapa, North Island, New Zealand. Laboratory and statistical techniques are employed to assess the change in depositional environment prior to the onset of subduction. The results provide insights into the modes of deposition, stratigraphic evolution of the passive margin sequence and tectonic setting of the receiving basin before subduction initiation of the Hikurangi margin.

Gli stili APA, Harvard, Vancouver, ISO e altri

38

Blank, Jonathan M. "Late Eocene - Early Oligocene sequence stratigraphy of the nearshore-transition zone Latrobe Group, Ninety Mile Beach, Gippsland Basin /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09S.B/09s.bb642.pdf.

Testo completo

Abstract (sommario):

Thesis (B.Sc.(Hons.))--University of Adelaide, National Centre for Petroleum Geology and Geophysics, 2000. Volume 2 holds ten folded enclosures (some col.) in a box. Includes bibliographical references (4 leaves).

Gli stili APA, Harvard, Vancouver, ISO e altri

39

Abdou, Soliman Fathy Hussien. "The stratigraphy and sedimentology of Middle and Late Eocene carbonates of the Nile Valley, Egypt : a basinal analysis." Thesis, Swansea University, 1988. https://cronfa.swan.ac.uk/Record/cronfa42551.

Testo completo

Abstract (sommario):

Carbonate sediments in the northern Nile Valley were subjected to stratigraphical and sedimentological studies which led to a complete basinal analysis. Initiation of this basin occurred in the early Late Eocene at 40 MY. A workable lithostratigraphy is developed to group the various Formations (Beni Suef, Birket Qarun, Saqqara, the Qurn, and the Wadi Hof) under one regional rock unit; the Middle Mokattam Unit. Biostratigraphical zonations were adapted, by means of nannoplankton and (both micro and larger) foraminifera, to date the strata as closely as possible and to achieve chronostratigraphical correlations. Onlap-offlap and facies interfingering relationships are recorded and discussed. The stratigraphical investigation has shown the presence of a depositional basin (Middle Mokattam basin) and detected its outline. Sedimentological studies and detailed modal analysis of carbonate grains have identified 12 major facies and 36 microfacies associations. These have clarified the depositional environments which occupied the basin. Careful basinal analysis, for both stratigraphical and sedimentological investigations, together with paleoecological determination of carbonate grains and communities, were used to reveal the basin configuration. Soft sediment deformation is also recorded and used to interpret the pattern of syndepositional subsidance which was controlled by rejuvenated deep-seated faults. Recurring uplift of the external northwestern block shaped the basin and controlled the depositional processes. This was responsible for an influx of residemented deposits derived either from nearby shelves or from adjacent paleohighs. The resedimented deposits formed deeply chajinelled fans and clastic barriers. The basin exhibits abundant evidence of synchronous tectonic uplift and sedimentation. Features such as growth femits, syn-sedimentary and syn-tectonic unconformities, debris and mass gravity flow deposits demonstrate a direct link between sedimentation and tectonism, and highlight the episodic nature of uplift in the external parts of the basin. This uplift resulted in the syn-sedimentary southward shifting of the depositional axis.

Gli stili APA, Harvard, Vancouver, ISO e altri

40

Chanvry, Emmanuelle. "Caractérisation et facteurs de contrôle des distributions minéralogiques du Bassin Piggyback de Graus-Tremp-Ainsa (Espagne), à l’Eocène Inférieur." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEM034/document.

Testo completo

Abstract (sommario):

Cette thèse propose une méthodologie pour caractériser et intégrer les distributions minéralogiques des dépôts de l’Eocène Inférieur du Bassin de Graus-Tremp-Ainsa dans un cadre séquentiel reconstruit à haute résolution. Le couplage des approches stratigraphiques et géochimiques/minéralogiques permet d’évaluer la part des forçages tectoniques, climatiques, eustatiques et diagénétiques sur l’enregistrement sédimentaire et minéralogique du bassin. La caractérisation de la minéralogie repose sur un calcul automatisé utilisant la géochimie multi-élémentaire et calibré ponctuellement par les outils d’analyse minéralogique conventionnels (pétrographie, DRX, Qemscan, microsonde). Elle a l’avantage de permettre de traiter les évolutions minéralogiques à l’échelle du bassin et sur l’ensemble des lithologies rencontrées. Après avoir évalué les effets de la diagenèse, du tri hydrodynamique et reconstitué la composition minéralogique primaire des sédiments, nous caractérisons les différentes sources.Nous précisons l’évolution de la tectonique (avec un pas de temps de l’ordre du million d’années) et ses effets sur l’architecture sédimentaire et la minéralogie des dépôts. Ceux-ci montrent un contrôle spatial de la diagenèse et des changements spatio-temporels des sources, liés à une compétition entre la tectonique intrabassinale (activité des chevauchements locaux) et régionale (surrection de l’orogène et subsidence flexurale). Nous montrons également que l’impact de la tectonique est modulé par des anomalies climatiques ponctuelles de l’ordre de la centaine de milliers d’années (PETM, ELMO, X-Event), que nous avons reconnues par un changement marqué des environnements de dépôt et des cortèges argileux.Deux grands épisodes régionaux caractérisent l’évolution du Bassin piggyback de Graus-Tremp-Ainsa. Le stade précoce, d’âge Ilerdien-Cuisien Inférieur, est marqué par le passage d’une rampe carbonatée mixte à des systèmes deltaïques alimentés depuis l’orogène pyrénéen par des contributions plutoniques. Cet ensemble passe ensuite à un vaste système fluvio-deltaïque au Cuisien Inférieur / Moyen, montrant l’apport de lithiques carbonatés et silicoclastiques qui coïncide avec l’émergence des nappes sédimentaires. La fin de cet épisode est marquée par la propagation du chevauchement du Montsec et de ses rampes latérales, provoquant un partitionnement du bassin, induisant la surrection du Bassin de Graus-Tremp et une forte subsidence du Bassin d’Ainsa. Ce contraste de subsidence est souligné par un partitionnement de la diagenèse, avec une kaolinisation des formations supérieures du Bassin de Graus-Tremp, liée à la percolation d’eaux météoriques, et, dans le Bassin d’Ainsa, une albitisation des grès couplée à une illitisation des smectites dans les lutites, liée à une diagenèse d’enfouissement plus marquée We develop here a methodology to integrate the mineralogical record into a high resolution sequence stratigraphic framework realized in the Early Eocene Graus-Tremp-Ainsa Basin. Coupling stratigraphic with geochemical and mineralogical approaches allows us to unravel the effects of tectonics, climate, eustasy and diagenesis on basin architecture and mineralogy. An automated computed mineralogy is derived from whole-rock geochemical data, and calibrated against direct mineral quantifications (petrography, DRX, Qemscan, microprobe). It provides a basinscale view of mineral distribution, irrespective of the lithology. Diagenetic overprint and hydrodynamic sorting effects are evaluated first, then primary mineral distributions are reconstructed and ascribed to different types of sediment sources.We show that, at the million-year timescale, tectonics shape the architecture and the mineralogy of the deposits. Spatially distributed diagenesis and temporal and spatial changes in sediment sources reflect the competing effects of intrabasinal tectonics (local thrust displacements) versus basinscale flexural subsidence linked to the orogen uplift and loading. Tectonically-driven changes are also sensitive to higher frequency (100 ky) anomalic climatic events (PETM, ELMO, X-EVENT) leaving a mineralogical signal in clay fractions and environment deposits succession.The basinscale evolution displays two contrasting stages. During the Ilerdian to the lower Cuisian, a mixed carbonate ramp evolves to a set of deltaic fans of Northern (Pyrenean orogen) provenance delivering plutonic-dominated materials. Then, during the lower/mid Cuisian, they are overprinted by a large fluvial and deltaic system bringing recycled carbonates and siliciclastics sourced in the emerging eastern to southern sedimentary thrust sheets. Later on, the propagation of the Montsec thrust and its lateral ramp decouples the uplifted Graus-Tremp basin from the strongly subsiding Ainsa basin. These different subsidizing schemes are underlined diagenetic overprints diverge, with an extensive kaolinisation of the uppermost units in the Graus-Tremp Basin driven by meteoric fluid circulations, and a severe albitisation of sandstones in the Ainsa basin, coupled with the illitisation of smectites in the lutites and caused by deep basinal fluids

Gli stili APA, Harvard, Vancouver, ISO e altri

41

Lafont, François. "INFLUENCES RELATIVES DE LA SUBSIDENCE ET DE L'EUSTATISME SUR LA LOCALISATION ET LA GEOMETRIE DES RESERVOIRS D'UN SYSTEME DELTAÏQUE. Exemple de l'Eocène du bassin de Jaca, Pyrénées espagnoles." Phd thesis, Université Rennes 1, 1994. http://tel.archives-ouvertes.fr/tel-00653783.

Testo completo

Abstract (sommario):

Le propos du travail présenté ici est de montrer les influences respectives de l'eustatisme et de la tectonique sur l'enregistrement stratigraphique d'une série deltaïque dans un bassin d'avant-pays. L'étude a reposé principalement sur l'interprétation en stratigraphie séquentielle haute résolution de données de terrain, acquises dans le bassin de Jaca (Pyrénées espagnoles, Province de Huesca). Il est présenté en premier lieu une synthèse faisant l'état des connaissances sur la méthode d'étude, c'est à dire la stratigraphie séquentielle, sur le problème posé, soit les influences relatives de la tectonique et de l'eustatisme sur l'enregistrement stratigraphique, et enfin sur le cadre géologique régional de bassin de Jaca. La première partie de l'étude proprement dite a été une interprétation sé d imentolo~ique des dépôts de l'Eocène supérieur du bassin de Jaca. Il est proposé une description exhaustive de tous les faciès sédimentaires, avec leur interprétation en termes de mécanismes de dépôt et de milieux de sédimentation. L'analyse des associations verticales préférentielles de faciès a permis de mettre en évidence l'existence de quatre grands types de systèmes sédimentaires : des rampes de tempêtes à basse énergie, des deltas de piémont à réseaux en tresses, des deltas *vrais* à dominante d'hydrodynamique fluviatile, et des sy.stèmes d'estuaires et de replats de marées. L existence de différents types de systèmes sédimentaires a conduit à établir plusieurs diagrammes de substitution de faciès, qui ont servi de base aux interprétations en stratigraphie séquentielle haute résolution. F'aisant suite à l'établissement du cadre sédimentologique, est abordé le problème de la reconstitution des géométries stratigraphiques à toutes les échelles. Il est montré une description à très haute résolution (résolution verticale inférieure à un mètre) d'une formation deltaïque de la bordure nord du bassin -les Grès de Sabinanigo-et une reconstitution à haute résolution, à partir des affleurements de la bordure sud. Les résultats de cette approche Qéométrique ont conduit à proposer une modification de la démarche d'analyse en stratigraphie séquentielle haute résolution dans un contexte à très fort contrôle structural synsédimentaire, en privilégiant la corrélation par dénombrement des unités stratigraphiques plutôt que la corrélation de tendances évolutives. Il est présenté ensuite les résultats de l'étude de données de sismique,avec une discussion sur la géométrie générale des dépOts éocènes dans le bassin. et la proposition d'un modèle expliquant la genèse d'une série d'anticlinaux d'axe méridien dans la bordure sud du bassin. La compréhension du cadre sédimentologique et des géométries a permis de répondre à la question initiale de la distinction des influences respectives de la tectonique et de l'eustatisme. Il est montré que chaque ordre de variation allocyclique enregistré dans la série peut être rapporté à un phénomène précis (tectonique ou eustatique). Il est mis en évidence la superposition d'au moins deux ordres de variation eustatique à haute (quelques dizaines de milIIiers d'années) et moyenne (quelques centaines de milliers d'années) fréquences. Les amplitudes de ces variations seraient de l'ordre de quelques mètres. Ces variations eustatiques contrôlent l'architecture haute résolution de la série et provoquent des modifications rapides dans le temps de la nature des systèmes sédimentaires. tl est montré par ailleurs l'influence d'au moins deux ordres de variations tectoniques: des mouvements à courte longueur d'onde (plis, failles) qui contrOle nt ta géométrie et l'emplacement des corps sédimentaires, et un mouvement de moyenne à grande longueur d'onde (flexuration du bassin), qui détermine la variation à long terme dans le temps et l'espace de la position des systèmes cfe dépôt. Cette déformation régionale est capitale, dans la mesure où elle permet à tous les autres facteurs de contrôle d'être enregistrés, par la création permanente d'accomodation.

Gli stili APA, Harvard, Vancouver, ISO e altri

42

Menkveld-Gfeller, Ursula. "Stratigraphie und Palaeogeographie des Eocaens der helvetischen Decken der Westschweiz (Diablerets- und Wildhorn-Decke) /." Bern : Universität Philosophisch-naturwissenschaftlichen Fakultät, 1993. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

43

Taubert, Samuel M. "Seismic stratigraphy and palaeogeography of the Early Paleocene to Mid Eocene of the Dampier Sub-Basin, North West Shelf, Australia /." Title page and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09SB/09sbt222.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

44

Holmström, Max. "Eocene-Oligocene Benthic Foraminifera Stable Isotope Stratigraphy and Paleoceanography of ODP Site 757 and 756, Ninetyeast Ridge, Southern Indian Ocean." Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-107074.

Testo completo

Abstract (sommario):

The EOT is marked by a two-step shift in the δ18O record of benthic foraminifera. The transition was rapid (500 000 years) and occurred roughly 34 million years ago. It marks an important step in Earth’s climate history where semi-permanent ice-sheets developed over Antarctica and is considered the initiation of the modern glaciated climate that the Earth experience today. Ninetyeast Ridge is a hot spot trail in the Indian Ocean that was formed by the Keguelen/ Ninetyeast hotspot and was one of the drilling targets of ODP leg 121 and among other sites 757 and 756 were drilled. To gain a better understanding of the paleoceanography and better constrain the timing of the EOT in the Indian Ocean, benthic foraminifera stable isotopes in Cibicidoides havanensis was analysed at site 757B and Cibicidoides mundulus at site 756C and was then age calibrated using an age model. The results indicate that the significant two-step shift that characterizes the EOT is present at Site 757B. However the results also indicate that it is not sufficient to use an age model that assumes a constant sedimentation rate since it changed drastically at this site at the E-O boundary. Finally the results indicates that there may have been several water masses operating simultaneously in the Indian Ocean at the EOT, the water masses discussed as most likely in this thesis is AAIW and TISW.

Gli stili APA, Harvard, Vancouver, ISO e altri

45

Le, Callonnec Laurence. "Apports de la geochimie des carbonates pelagiques a la stratigraphie et la paleo-oceanographie du paleocene et de la limite paleocene/eocene." Paris 6, 1998. http://www.theses.fr/1998PA066545.

Testo completo

Abstract (sommario):

Le paleocene est delimite par deux crises biologiques : a la limite k/t (extinction des organismes planctoniques) et au paleocene terminal (disparition d'organismes benthiques). Ces crises sont contemporaines de bouleversements paleo-oceanographiques et paleoclimatiques se caracterisant geochimiquement par un accident negatif du 1 3c et une chute des teneurs en strontium. Une etude geochimique ( 1 3c, 1 8o et elements traces) a ete entreprise, sur carbonate pelagique total, pour la tethys, suivant un transect no/se (pays basque, italie, israel, et oman). Les deux objectifs principaux de ce travail sont : - de determiner les causes principales des variations geochimiques, en faisant la part des phenomenes regionaux et des phenomenes mondiaux ; - de contraindre par la chimiostratigraphie la position de la limite paleocene/eocene. Les variations du 1 3c traduisent a la fois les modifications de la productivite planctonique et de la fossilisation du carbone organique dans les oceans. Ces conditions sont optimales au paleocene superieur, tandis qu'au paleocene inferieur, la reprise de la productivite n'est pas encore totalement retablie suite a la crise k/t. Au passage paleocene/eocene, une derive negative du 1 3c s'observe. L'evolution des teneurs en strontium reflete les modifications de la productivite neritique associees aux cycles transgressifs/regressifs de second ordre. Deux excursions positives, a la base du paleocene superieur et au paleocene terminal, marquent des transgressions et un developpement des plates-formes carbonatees. L'enregistrement du 1 8o met en evidence un refroidissement des eaux oceaniques au paleocene superieur. Les variations des teneurs en manganese suivent assez bien les cycles eustatiques de troisieme ordre. La comparaison des donnees tethysiennes avec celles des sites oceaniques met en evidence l'influence de la paleoprofondeur sur le 1 3c dans les oceans en cours d'ouverture et en cours de fermeture, et le role de la paleolatitude dans le domaine tethysien. Le 1 3c permet de preciser la localisation stratigraphique de la limite p/e qui se situe dans la derive negative (biozones np8 a np11/np12), apres l'accident negatif contemporain de la crise des benthiques et se correlerait avec la limite p5/p6.

Gli stili APA, Harvard, Vancouver, ISO e altri

46

Taylor, Andrew W. "Sedimentology, Facies Architecture, and Reservoir Characterization of Lacustrine Rocks, Eocene Green River and Colton Formations, Uinta Basin, Utah." DigitalCommons@USU, 2002. https://digitalcommons.usu.edu/etd/6780.

Testo completo

Abstract (sommario):

Outcrop and petrographic studies of the Eocene Green River and Colton formations in the Uinta basin, Utah, document the facies architecture and heterogeneity characteristic of lacustrine reservoirs. A southwest-northeast transect of Eocene strata in the Uinta basin records three main marginal lacustrine depositional environments: fluvial, deltaic, and wave-dominated. Heterogeneity exists between and within individual depositional systems. Reservoir rocks of Outcrops One and Two (the flu vial facies of the Colton Formation and the deltaic facies of the Green River Formation, respectively) consist of 2 to 18 m thick lenticular, tabular, or undulatory channel-fill, distributary channel, and distributary mouth bar deposits that are partially to entirely compartmentalized, or encased, by mudstone units. These reservoir analog intervals are dominated by large scale heterogeneity, in that sand bodies show a variety of connectivity and lateral continuity. Small-scale heterogeneity exists within these sand bodies in the form of mud chip lag surfaces, large mud clast horizons, and discontinuous finer-grained beds. These features add complexity to the systems by reducing flow transmissibility or acting as flow baffles. The complex heterogeneity characteristic of these reservoir analogs confirms the need for detailed reservoir characterization studies on all scales in order to improve exploration and production efficiency in such systems. Outcrop Three (the wave-dominated facies of the Green River Formation) is dominated by thinner (2 to 4 m) tabular and laterally extensive offshore bar deposits that are compartmentalized by mudstone units. Large-scale heterogeneity is minimized in these reservoir analogs, in that sand bodies exhibit excellent lateral continuity and less complex amalgamation. Therefore, documentation of the smaller-scale heterogeneities (similar to those mentioned in the previous two outcrops) is necessary to better address exploration and production potential in these types of reservoirs. Data collected in this study were utilized in geostatistical simulations and fluid flow models in an attempt to document the effects of reservoir heterogeneity on hydrocarbon exploration and production efficiency in lacustrine basins. Further studies of this type are necessary if predictable classification systems and hierarchies of bounding surfaces are to be derived for lacustrine reservoirs. (152 pages)

Gli stili APA, Harvard, Vancouver, ISO e altri

47

Pelletier, Jonathan. "Faciès, architecture et dynamique d’un système margino-littoral tidal : exemple de la Formation du Dur At Talah (Eocène supérieur, Bassin de Syrte, Libye)." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAH016/document.

Testo completo

Abstract (sommario):

Ce manuscrit de thèse propose la première étude sédimentologique exhaustive de l’escarpement du Dur At Talah (150 km de long sur 120 m de hauteur). Ce dernier affleure dans la dépression d’Abu Tumayam, dans la partie méridionale du Bassin de Syrte (Libye). La Formation du Dur At Talah offre une séquence sédimentaire régressive (au 2nd ordre), allant de faciès marins peu profonds à des faciès fluviatiles, datée de l’Eocène supérieur. Les exceptionnelles conditions d'affleurement ont permis une analyse sédimentologique approfondie (lithofaciès, ichnofaciès, géométries et découpage séquentiel) conduisant à une caractérisation multiscalaire d'un système margino-littoral dominé par la dynamique tidale. Parmi les résultats saillants de cette étude figure l'identification de deux processus sédimentaires : la progradation signée par des structures clinoformes et l’accrétion latérale caractérisée par des stratifications hétérolithiques inclinées (IHS). Dès lors, plusieurs corps sédimentaires se distinguent sans ambiguïté tel que les barres d’embouchure hétérolithiques et les barres de méandres de chenaux tidaux. L'auscultation de ces grands corps sédimentaires permet alors d'en définir les critères de reconnaissance et le contexte séquentiel de mise en place, mais aussi d'en contraindre le potentiel réservoir This manuscript provides the first exhaustive sedimentological study of the Dur At Talah escarpment (≈120 m high and ≈150 km length). This latter is exposed in the Abu Tumayam Trough, in the southern Sirt Basin (Libya). The Dur At Talah Formation forms a 2nd order regressive sequence, from shallow marine to fluviatile deposits, dated as upper Eocene. This exceptional outcrop allows an extensive and detailed sedimentological analysis (lithofaciès, ichnofaciès, geometries and sequence stratigraphy) leading to a multi-scale characterization of nearshore to paralic environments dominated by tidal dynamic. Among outstanding results, two sedimentary processes have been recognized and characterized: the progradation is expressed by large-scale clinoform structures and the lateral accretion is characterized by inclined heterolithic stratifications (IHS). Several sedimentary bodies are, thus, unequivocally distinguishable such as heterolithic mouth-bars and tidal channel point-bars. Thorough analysis of these sedimentary bodies allows to define diagnostic criteria to recognize them. They can be replaced in a consistent stratigraphic framework explaining their architecture and their vertical evolution in order to be used as reservoir analog

Gli stili APA, Harvard, Vancouver, ISO e altri

48

Crumeyrolle, Philippe. "Stratigraphie physique et sédimentologie des systèmes de dépôt de la séquence de Santa Liestra : Eocène sud-pyrénen, Pyrénées aragonaises, Espagne." Bordeaux 3, 1987. http://www.theses.fr/1987BOR30208.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

49

Batiston, Denis Antonio. "Modelo geológico conceitual do paleocânion de Regência, região onshore da Bacia do Espírito Santo, Cretáceo ao Eoceno /." Rio Claro, 2018. http://hdl.handle.net/11449/180232.

Testo completo

Abstract (sommario):

Orientador: Rosemarie Rohn Davies Banca: Norberto Morales Banca: Maria Gabriela Castillo Vincentelli Resumo: O paleocânion de Regência é reconhecido em subsuperfície da bacia do Espírito Santo, localizado nas proximidades da foz do Rio Doce (ES), originado no Cretáceo e preenchido até meados do Eoceno. Dados de 31 seções sísmicas, 29 poços e marcadores bioestratigráficos (definidos por nanofósseis calcários) substanciaram a elaboração de modelos geológicos que aprimoram o conhecimento sobre a evolução do paleocânion. Os resultados incluem correlações estratigráficas, interpretações de feições estruturais e das principais superfícies estratigráficas no âmbito das formações Mariricu, São Mateus, Regência e Urucutuca, assim como seções esquemáticas transversais e longitudinais do paleocânion, mapas de contorno estrutural dos topos litoestratigráficos e de contorno morfológico do paleocânion. Estas informações foram integradas em detalhe para discutir sua origem, o preenchimento e os fatores de controle. Desde o início, o paleocânion foi estruturado por falhas no embasamento. Próximo ao topo da Formação Mariricu, de idade aptiana, já há indícios de uma extensa calha rasa. O paleocânion é dividido pela Zona de Charneira Cedro-Rio Doce (ZCCRD), que é um sistema de falhas normais de direção praticamente N-S. A morfologia e a largura do paleocânion também foram controladas por diversas falhas normais menores nos blocos proximal e distal à ZCCRD, originadas no embasamento, ainda ativas quase até o final do preenchimento do paleocânion, com direção principalmente SO-NE. Falhas normais também ... (Resumo completo, clicar acesso eletrônico abaixo) Abstract: Santo Basin, located near to the mouth of the Doce River (State of Espírito Santo, Southeast Brazil), carved from the Cretaceous and filled up to the mid Eocene. Data of 31 seismic sections, 29 wells and biostratigraphic markers (of calcareous nannofossils) have substantiated the conception of geological models that improve the awareness concerning the paleocanyon evolution. The results include stratigraphic correlations, structural geology interpretations and stratigraphic surfaces determination within the Mariricu, São Mateus, Regência and Urucutuca formations, as well as schematic transversal and longitudinal sections of the paleocanyon, structural contour maps of the lithostratigraphic tops and morphologic contour map of the paleocanyon. These information were integrated in detail to promote discussion about the origin, the filling and the controls of the paleocanyon development. Since the beginning, the structure was related to faults in the basement. The first long shallow channel is evidenced near the top of the Aptian Mariricu Formation. The paleocanyon is divided into a proximal block and a distal one by an almost N-S system of normal faults designated as Cedro-Rio Doce Fault Zone (CRDFZ). In both blocks, the morphology and width of the paleocanyon were also controlled by several smaller normal faults with main SW-NE direction, originated in the basement, still moving until the almost complete fill of the paleocanyon, with main direction SW-NE. Normal faults were als... (Complete abstract click electronic access below) Mestre

Gli stili APA, Harvard, Vancouver, ISO e altri

50

Coiffait, Philippe-Emmanuel. "Un bassin post-nappes dans son cadre structural : l'exemple du bassin de Constantine (Algérie nord-orientale)." Nancy 1, 1992. http://www.theses.fr/1992NAN10412.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Tesi sul tema "Stratigraphic Eocene"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili