Dissertationen zum Thema „Geology, Stratigraphic Eocene“
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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.
Annotation:
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.
2
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.
Annotation:
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.
3
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.
Annotation:
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.
4
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.
Annotation:
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.
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.
Annotation:
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).
6
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.
7
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.
Annotation:
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.
8
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.
9
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.
Annotation:
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.
10
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.
Annotation:
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
11
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.
Annotation:
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
12
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.
Annotation:
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.
13
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.
Annotation:
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.
14
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.
15
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.
Annotation:
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.
16
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.
Annotation:
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 setsseismic 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.
17
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.
Annotation:
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).
18
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.
Annotation:
The aim of this study is to investigate the nature of the meter-scale
cycles in the Çayraz 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 Ç
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 Ç
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 Ç
ayraz Formation.
19
Edgar, Kirsty M. „Palaeoclimatology, stratigraphy and biotic responses in the middle Eocene“. Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/65670/.
Annotation:
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.
20
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.
21
Rancan, Cristiano Camelo. „Estratigrafia da série eoceno no Baixo do Mosqueiro, bacia de Sergipe-Alagoas /“. Rio Claro, 2017. http://hdl.handle.net/11449/151380.
Annotation:
Orientador: Rosemarie Rohn DaviesCoorientador: 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
22
King, Christopher. „Stratigraphy of the London Clay Formation (Early Eocene) in the Hampshire Basin“. Thesis, Kingston University, 1991. http://eprints.kingston.ac.uk/20552/.
Annotation:
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.
23
Anderson, Alvin D. „Geology of the Phil Pico Mountain Quadrangle, Daggett County, Utah, and Sweetwater County, Wyoming“. Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2384.pdf.
24
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.
Annotation:
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.
25
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.
Annotation:
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)
26
Fanton, Jean Carlo Mari 1983. „Reconstruindo as florestas tropicais úmidas do eoceno-oligoceno do sudeste do Brasil (Bacias de Fonseca e Gandarela, Minas Gerais) com folhas de fabaceae, myrtaceae e outras angiospermas : origens da Mata Atlântica“. [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287244.
Annotation:
Orientador: Fresia Soledad Ricardi Tores BrancoTese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociências
Made available in DSpace on 2018-08-22T19:10:06Z (GMT). No. of bitstreams: 1 Fanton_JeanCarloMari_D.pdf: 19867542 bytes, checksum: 5b38f9327cfcd9fa334e56499a15d4bc (MD5) Previous issue date: 2013
Resumo: Folhas isoladas de angiospermas preservadas em depósitos fluvio-lacustres das bacias de Fonseca e Gandarela foram analisadas visando reconstruir o paleoambiente. Angiospermas são bons indicadores climáticos, pois a distribuição de suas espécies no espaço/tempo e influenciada pelo clima. Localizadas no centro-sul de Minas Gerais, as bacias de Fonseca e Gandarela são grabens encravados no embasamento Pré-Cambriano, depositados nos intervalos Neoeoceno-Eoligoceno e Neoeoceno- Eomioceno (respectivamente), segundo dados paleológicos. Como métodos, alem da morfotipificação, características arquiteturais informativas permitiram identificações taxonômicas com base apenas em folhas. Para estimar as paleotemperaturas, aplicou-se a Analise da Margem Foliar (LMA) utilizando a relação entre a proporção de espécies arbóreas "dicotiledôneas" com margens lisas (pE) e a media anual de temperatura (MAT). Antes, a habilidade de modelos sul-americanos foi testada em florestas atlânticas do sudeste. Devido à pEs altas (0,78-0,87), as temperaturas dos locais quentes-baixos (MAT ? 23°C) foram estimadas corretamente, mas o erro foi maior nos locais frios-elevados (MAT ? 22°C, 610-890 m). Mesmo que linhagens obrigatoriamente lisas estiveram super-representadas tanto nos locais quentes quanto frios (em media 38% das espécies/local), o desenvolvimento de terras altas desde o Neocretaceo e Cenozóico no sudeste inviabiliza hipóteses de tempo insuficiente para a evolução de margens denteadas nas angiospermas adaptadas a altitude. Para Fonseca (40 morfotipos) e Gandarela (20) foram obtidas pEs tão altas (0,90 e 0,95) quanto às de florestas equatoriais amazônicas atuais. MATs ? 24,7°C foram reconstruídas pela maioria dos modelos (em media ?27-28°C), faixa megatermica hoje registrada principalmente em terras-baixas do norte e nordeste do Brasil. Mais da metade dos 25 morfotipos aqui descritos foram identificados em famílias tropicais, como Lauraceae (FS06, GR03 e GR09), Fabaceae (FS01-03, FS05, FS09 e GR08), Combretaceae (FS08) e Myrtaceae (FS11-13 e GR02). Todas são linhagens com uma longa historia evolutiva (no mínimo desde o Paleoceno-Eoceno) no norte (Fabaceae e Lauraceae) e no sul (Myrtaceae) da America do Sul, expondo um antigo legado de tropical idade e influencia floristica mista (boreal-laurasiana e austral-antartica). Hoje no sudeste, tais famílias controlam boa parte dos recursos ecológicos na Mata Atlântica e provavelmente já o faziam nas florestas do Neopaleogeno. Devido à composição e certas condições ambientais compartilhadas, as florestas ombrofilas do compartimento sul da Mata Atlântica (inclusive a Floresta Ombrofila Mista, FOM) são analogias modernas parcialmente comparáveis com Fonseca e Gandarela: temperaturas e pluviosidade elevadas mantendo um dossel sempre-verde e multiestratificado, dominado por angiospermas (Myrtaceae, Lauraceae e Fabaceae) e coníferas austrais (Podocarpaceae e Araucariaceae). Confirmam a reconstrução de florestas tropicais úmidas: (1) o conjunto fisionômico da Formação Fonseca (onde 40- 65% dos morfotipos avaliados têm ápice acuminado, 80-90% margens lisas e 50% notofilo-mesofilos) e (2) a presença de linhagens que demandam umidade e intolerantes ao frio, como podocarpaceas dacrydioides (Dacrydiumites) e mirtaceas como FS13 (identificado em Curitiba), exibindo uma folha acuminada 2× maior que da atual C. prismática, espécie endêmica da FOM. O cenário reconstruído se ajusta aos níveis superiores de CO2 atmosférico, maior zona tropical e invernos relativamente brandos do final do Paleogeno
Abstract: Isolated fossil angiosperm leaves preserved in fluvial-lacustrine deposits from the Fonseca and Gandarela basins were analyzed to reconstruct the paleoenvironment. Angiosperms are good climatic indicators since the species distribution in space/time is influenced by the climate. Located in central-southern part of the State of Minas Gerais, the Fonseca and Gandarela basins are grabens embedded in the Precambrian basement, deposited during the Late Eocene-Early Oligocene interval, according to palynological data. As methods, informative architecture characteristics allowed taxonomic identifications solely on the basis of leaves. To estimate paleotemperatures, the Leaf Margin Analysis (LMA) was applied, based on the relationship between the proportion of untoothed woody "dicot" species (pE) and mean annual temperature (MAT). Before, the ability of South American models was tested on modern sites of Atlantic forests from southeastern Brazil. Because of high pEs (0,78-0,87), temperatures of the low-elevation sites (MAT ? 23°C) were predicted accurately, but the error was greater in the high-elevation ones (MAT ? 22°C, 610-890 m). Although obligate untoothed lineages were richly represented in low and high-temperature sites (in average 38% of the species per site), the development of highlands in southeastern Brazil since the Late Cretaceous and Cenozoic invalidate hypotheses about an insufficient time to evolve teeth in angiosperms adapted to high-elevations. Both fossil floras Fonseca (40 morphotypes) and Gandarela (20) showed pEs (0,90 and 0,95) so high as observed in Amazonian equatorial rainforests. MATs ? 24,7°C were yielded for the majority of the models (in average ?27-28°C), isotherm today registered mainly in lowlands from northern Brazil. Over half of the morphotypes described were identified in families essentially tropical, such as Lauraceae (FS06, GR03 and GR09), Fabaceae (FS01-03, FS05, FS09 and GR08), Combretaceae (FS08) and Myrtaceae (FS11-13 and GR02). All these lineages have a long evolutionary history (since at least the Paleocene- Eocene) in the north (Fabaceae and Lauraceae) and south (Myrtaceae) of South America, revealing an antique legacy of tropicality and mixed floristic influence from boreal-laurasian and austral-Antarctic regions. Today, such families have controlled a major portion of the ecological resources in the Atlantic forests from southeastern Brazil probably retaining dominance since the Paleogene. Similar composition and some environmental aspects suggest that the rainforests from the southern Atlantic block (including Araucaria rainforest) are the closest living analogues to the Fonseca and Gandarela extinct vegetation: high temperatures and heavy rainfall sustaining an evergreen and multilayered canopy dominated by angiosperms (Myrtaceae, Lauraceae and Fabaceae) and austral conifers (Podocarpaceae and Araucariaceae). Additional evidence supporting the tropical rainforest hypothesis is: (1) the Fonseca Formation leaf physiognomy (40-65% of the morphotypes evaluated have drip tips, 80-90% untoothed margins and 50% are notophyll-mesophyll), and (2) the presence of water-demanding and coldintolerant lineages, such as dacrydioid podocarps (Dacrydiumites) and the Myrtaceae morphotype FS13 (identified as Curitiba), which bears an acuminate leaf 2× longer than the extant C. prismatica. The paleoenvironment reconstructed agree with the higher atmospheric CO2 levels, the wider Tropical zone and the relatively mild winters during the Late Paleogene
Doutorado
Geologia e Recursos Naturais
Doutor em Ciências
27
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.
Annotation:
Orientador: Rosemarie Rohn DaviesBanca: 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
28
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.
Annotation:
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.
29
Claudel, Marie-Elisabeth. „Reconstitution paléogéographique du domaine briançonnais au Mésozoïque : ouvertures océaniques et raccourcissements croisés“. Phd thesis, Grenoble 1, 1999. http://tel.archives-ouvertes.fr/tel-00509949.
Annotation:
La zone briançonnaise est issue d'un domaine de la marge passive de la Téthys ligure, qui a émergé au Jurassique. Elle est actuellement située au cœur de l'arc alpin entre la zone externe et les autres zones internes. L'évolution particulière de ce domaine pose le problème de sa localisation paléogéographique au sein de la marge passive. En effet, les séries briançonnaises des Alpes occidentales (Sud et du Pelvoux) montrent les traces de déformations anté-alpines antérieures ou postérieures au rifting jurassique de la Téthys ligure. L'analyse des marqueurs structuraux (failles normales, filons, hard-ground, ...) contenus dans la sédimentation associée aux études classiques de sédimentologie, stratigraphie et de micropaléontologie permettent d'établir une chronologie précise des évènements extensifs, de caractériser ces paléostructures et de mettre au jour l'évolution du domaine briançonnais tout au long du Mésozoïque et du Cénozoïque. Des variations d'épaisseurs de l'unité lithologique des « Calcaires rubanés » du Ladinien inférieur impliquent une subsidence différentielle d'origine tectonique (période antérift). Des phénomènes de dissociation trouvés à la limite Ladinien-Carnien pourraient correspondre à des ébranlements sismiques contemporains d'une structure syn-rift précoce de la plate-forme triasique. A partir de l'analyse diagénétique d'échantillons prélevés au niveau de la surface d'émersion, il semble que la lacune débute au Sinémurien supérieur sur l'aire de Peyre-Haute. Le rifting téthysien comprendrait 2 phases : au Carnien et au Sinémurien (surrection). En Briançonnais, 2 aires de subsidence distinctes discernables sur des courbes de subsidence ont donc été mises en évidence pour cette période. L'effondrement « post-rift » de la pate-forme briançonnaise au Bathonien supérieur est suivi par une nouvelle structuration au Callovien-Oxfordien créant de nouvelles failles [Claudel et al., 1997]. Les périodes d'activité tectonique du Crétacé sont surtout marquées par des réactivations de failles : à l'Aptien-Albien et au Turonien supérieur. Les brèches du Campanien-Maastrichtien pourraient s'être déposées en contexte de convergence. L'analyse structurale montre l'existence de chevauchements hors-séquences au sein de l'édifice de nappes briançonnaises : la direction de chevauchement des charriages éocènes seraient obliques (vers le nord ?) par rapport aux charriages vers l'ouest oligocènes. La 1ère mise en place de nappes (Peyre-Haute et Prorel) est superficielle et marquée par des olistostromes (Eychauda, Queyrelets). L'analyse paléomagnétique préliminaire [Thomas et al., soumis] suggère une rotation anti-horaire d'une quarantaine de degrés postérieure à toutes les phases de plissements post-nappes de l'ensemble de la zone briançonnaise étudiée. Le dépliage des unités tectoniques, prenant en compte la rotation et les transports vers le nord, a permis de proposer une reconstitution paléogéographique régionale qui replace le domaine briançonnais au sein du Sud Est de la France dans le prolongement est de la Provence jusqu'au Jurassique supérieur. Replacées dans le contexte géodynamique globale, ces structurations successives croisées au niveau du domaine briançonnais pourraient résulter d'interférences entre les cycles de rifting-ouverture océanique suivants décalés dans l'espace et dans le temps [Claudel & Dumont, soumis] : système Halstatt-Méliata au Ladinien inférieur ; système Atlantique Central-Téthys ligure au Carnien-Lias ; système Atlantique Nord-Golfe de Gascogne-domaine valaisan au Callovien-Oxfordien. La plate-forme triasique enregistrerait tout d'abord l'écho du rifting de l'océan Halstatt au Ladinien, puis subit le 1er stade du rifting téthysien dès le Ladinien supéruer-Carnien. La phase principale survenant au Lias se traduit en domaine briançonnais par une surrection ; ce qui permet d'admettre que ce domaine constituait l'épaulement du rift téthysien [Stampfi, 1993]. Après l'ouverture initiale de l'océan Téthysien ligure, le rifting valaisan oblique par rapport à la ride médio-téthysienne continue de structurer le domaine briançonnais situé dès lors à l'intersection de 2 zones de rupture crustale. Le Wombat plateau au large de l'Australie a subit une évolution de ce type et fournit une image analogue à celle proposée pour le domaine briançonnais au Mésozoïque.
30
Escalona, Alejandro. „Regional tectonics, sequence stratigraphy and reservoir properties of Eocene clastic sedimentation, Maracaibo Basin, Venezuela“. Thesis, 2003. http://wwwlib.umi.com/cr/utexas/fullcit?p3119517.
31
Abdel-Fattah, Zaki Ali. „Sedimentology, ichnology, and sequence stratigraphy of the Middle-Upper Eocene succession in the Fayum Depression, Egypt“. Phd thesis, 2009. http://hdl.handle.net/10048/663.
Annotation:
Thesis (Ph.D.)--University of Alberta, 2009.Title from PDF file main screen (viewed on Mar. 18, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Earth and Atmospheric Sciences, University of Alberta. Includes bibliographical references.
32
Zhang, Xiaodong. „Subsurface stratigraphy of the Eocene Cocoa Sand Member in Mississippi and Alabama“. 2013. http://liblink.bsu.edu/uhtbin/catkey/1741655.
Annotation:
The Eocene Cocoa Sand Member of Yazoo Formation is fine grained, moderately to well sorted, poorly cemented, quartz arenite. Surface exposures are poor, but it has been mapped from west Choctaw County, Alabama to eastern Jasper County, Mississippi. In the subsurface, the Cocoa Sand Member is identified by obvious protrusion both in Spontaneous and Resistivity Logs. Northeast to southwest cross-sections (perpendicular to the paleo-shoreline) and northwest to southeast cross-sections (parallel to the paleo-shoreline) were developed, along with isopach maps, to determine the sequence stratigraphic setting and a depositional model of the Cocoa Sand Member. Previous work has interpreted the Cocoa Sand Member as a shelf margin sand deposited as part of a lowstand systems tract or as a transgressive sand. Grain size analysis indicates that the sand coarsens upward and there is evidence in core that the upper contact of the Cocoa sand with the Pachuta Marl is sharp, representing an upper erosion surface. The presence of rip-up clasts at the base of the Cocoa sand member supports the presence of a transgressive surface at the contact with the North Twistwood Creek. Based on the sand thickness distribution as identified in the Cocoa Sand isopach map and cross sections, two sand ridges have been recognized extending nearly parallel to the paleoshoreline across the Mississippi and Alabama. A three stage model is presented suggesting the formation of these ridges during transgression with the source of the sand being from the eroded and reworked underlying North Twistwood Creek Member.Department of Geological Sciences
33
Lewis, Reed S. (Reed Stone). „Geology, geochemistry, and mineral potential of cretaceous and tertiary plutons in the eastern part of the Soldier Mountains, Idaho“. Thesis, 1990. http://hdl.handle.net/1957/38254.
34
Berkman, Thomas Anthony. „Surface-subsurface geology of the middle to upper Eocene sedimentary and volcanic rock units, western Columbia County, northwest Oregon /“. 1990. http://hdl.handle.net/1957/9481.
Annotation:
Thesis (M.S.)--Oregon State University, 1990.Typescript (photocopy). Includes mounted photographs. Includes folded plates in pocket. Includes bibliographical references (leaves 377-396). Also available via the World Wide Web.
35
Harrison, Michael Anthony. „The Uitoe Limestone of New Caledonia : a Middle Eocene syntectonic foralgal reef from the southwest Pacific“. 2013. http://liblink.bsu.edu/uhtbin/catkey/1741645.
Annotation:
A study of a poorly understood limestone unit was conducted to contribute temporal information necessary to unraveling a series of cryptic events for a complex geologic region containing economically important natural resources. Secondary objectives included understanding the environment of deposition and regional influences. Biostratigraphic and sedimentologic information observed from the Uitoé Limestone went to reconstructing the paleoenvironment, constraining the age of deposition and indicating the paleogeographic faunal associations. Facies associations indicate a middle ramp depositional setting common in many location in the Tethys Sea. Paleogeographic associations for the microflora and fauna indicate a Tethyan signature present but a lack of Australian influence. A combination of planktic and benthic foraminiferal assemblages for the region constrain the age of the Uitoé Limestone between the middle of the Lutetian and the Early Bartonian.Department of Geological Sciences
36
Moothart, Steve Rene'. „Geology of the middle and upper Eocene McIntosh Formation and adjacent volcanic and sedimentary rock units, Willapa Hills, Pacific County, southwest Washington /“. 1992. http://hdl.handle.net/1957/12293.
Annotation:
Thesis (M.S.)--Oregon State University, 1993.Includes mounted photographs. Three folded plates in pocket. Typescript (photocopy). Includes bibliographical references (leaves 213-225). Also available on the World Wide Web.
37
„Evolution of the Antarctic Peninsula continental margin from Late Eocene to present: Seismic stratigraphic analysis related to the development of the Antarctic Peninsula Ice Sheet (APIS)“. Thesis, 2009. http://hdl.handle.net/1911/61938.
Annotation:
This investigation into Antarctic Peninsula Ice Sheet (APIS) development represents research from the stratigraphic record of three geographic areas: The James Ross Basin (northwestern Weddell Sea), the Pacific continental margin of the Antarctic Peninsula, and the Joinville Slope (northwestern Weddell Sea).
The stratigraphic architecture of the James Ross Basin, NW Weddell Sea continental shelf, shows three major phases of deposition: pre-glacial, ice sheet growth, and ice sheet dominated. Each stratigraphic unit is characterized based upon seismic facies and stratigraphic architecture, and the ages are inferred from a seismic stratigraphic age model. A total of 34 grounding events of the Antarctic Peninsula Ice Sheet (APIS) are recorded on the continental shelf. The seven oldest glacial unconformities are believed to pre-date all previously identified unconformities on the peninsula continental shelf. An expanded section of Late Pliocene/Pleistocene deposits show a minimum of 10 grounding events.
Isopachs of sedimentary sequences on the Antarctic Peninsula Pacific continental margin show shifting depocenters through time. Chronostratigraphic and seismic depth-converted data from ODP 178 cores allow the calculation of sediment flux for shelf units S3-S1 and rise units M6-M1. Sediment flux to the margin increases from the Late Eocene until the Late Pliocene and then decreases slightly from Late Pliocene to present. Significant increases in sediment flux coincide with early development of the APIS and during the early Pliocene warming period (Barker and Camerlenghi, 2002). Minimum glacial denudation rates for the Antarctic Peninsula are in the range of 0.06 to 0.13 mm yr -1.
The Joinville Slope sediment wedge located in the northwestern Weddell Sea shows seismic stratigraphic evidence of mixed turbidite/contourite/hemipelagic deposition. A prominent seafloor unconformity and the exposed and eroded basement of the adjacent continental shelf indicate erosion by grounded ice during the Plio-Pleistocene. SHALDRIL recovered core at three drill sites, 12A, 5C, and 6D, and sampled sediments from the upper Oligocene, middle Miocene, and lower and upper Pliocene which are constrained by diatom and calcareous nannofossil assemblages. The sediment wedge shows no apparent hiatuses or large unconformities from Late Oligocene to the Lower Pliocene. Regional sedimentation rates show continuous sedimentation throughout the Late Paleogene and Neogene.
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Tsukui, Kaori. „Chronology and Faunal Evolution of the Middle Eocene Bridgerian North American Land Mammal “Age”: Achieving High Precision Geochronology“. Thesis, 2015. https://doi.org/10.7916/D8KS6R86.
Annotation:
The age of the Bridgerian/Uintan boundary has been regarded as one of the most important outstanding problems in North American Land Mammal “Age” (NALMA) biochronology. The Bridger Basin in southwestern Wyoming preserves one of the best stratigraphic records of the faunal boundary as well as the preceding Bridgerian NALMA. In this dissertation, I first developed a chronological framework for the Eocene Bridger Formation including the age of the boundary, based on a combination of magnetostratigraphy and U-Pb ID-TIMS geochronology. Within the temporal framework, I attempted at making a regional correlation of the boundary-bearing strata within the western U.S., and also assessed the body size evolution of three representative taxa from the Bridger Basin within the context of Early Eocene Climatic Optimum. Integrating radioisotopic, magnetostratigraphic and astronomical data from the early to middle Eocene, I reviewed various calibration models for the Geological Time Scale and intercalibration of 40Ar/39Ar data among laboratories and against U-Pb data, toward the community goal of achieving a high precision and well integrated Geological Time Scale.
In Chapter 2, I present a magnetostratigraphy and U-Pb zircon geochronology of the Bridger Formation from the Bridger Basin in southwestern Wyoming. The ~560 meter composite section spans from the lower Bridger B to the Bridger E, including the Bridgerian/Uintan NALMA boundary in the uppermost part of the section. Analysis of samples from 90 sites indicates two paleomagnetic reversals that are correlated to an interval spanning Chrons C22n, C21r, and C21n by comparison to the Geomagnetic Polarity Time Scale (GPTS). This correlation places the Bridgerian/Uintan faunal boundary within Chron C21n, during the initial cooling phase following the peak of the Early Eocene Climatic Optimum. Based on the bio- and magnetostratigraphic correlation, I provide correlation of other Bridgerian/Uintan boundary-bearing sections to the GPTS, demonstrating that in the western North America, the Bridgerian/Uintan boundary occurs everywhere in Chron C21n. In addition, U-Pb zircon geochronological analyses were performed on three ash beds from the Bridger Formation. High-precision U-Pb dates were combined with the paleomagnetic polarity data of the same ash beds as well as the integrative chronostratigraphy of the basin to assess prior calibration models for the Eocene part of the GPTS. The data from the Bridger Formation indicate that the Option 3 age model of Westerhold et al. (2008) best reconciles the geochronological data from all of the ash beds except for one. Thus I favor this Option 3 model, which indicates the ages of 56.33 Ma and 66.08 Ma for the Paleocene-Eocene Thermal Maximum and Cretaceous/Paleogene boundary, respectively.
In Chapter 3, the body size evolution of three mammalian taxa from the Bridgerian NALMA was analyzed within the context of Bergmann’s Rule, which poses a correlation between the size of endotherms and climate (latitude). The Bridgerian NALMA is from a time of global cooling following the peak of the Early Eocene Climatic Optimum, thus according to Bergmann’s Rule, the Bridgerian mammals are expected to increase in size. This hypothesis is tested among Notharctus, Hyopsodus, and Orohippus, using the size of molar dentition as a proxy for their body size. These taxa represent three different ecomorphs, and I investigated if these taxa showed a pattern of body size change consistent with the prediction made by Bergmann’s Rule, and how their ecological adaptation may have affected their response to the climate change. Prior to analyzing the body size evolution, specimens of Notharctus and Hyopsodus were identified to species based on dental characters. This practice differs from previous studies in which species identification relied on relative size of the individuals and stratigraphic levels of origin. Within the new framework of morphologically determined species identification, five species of Notharctus were recognized, among which, N. pugnax, N. robustior and N. sp. indet. exhibited statistically significant body size increase in the time span of interest. Based on morphological analyses of Hyopsodus dentition, I recognized five species. Dentition-based body size analysis showed that H. lepidus and H. despiciens exhibited a statistically significant change towards larger size within the sampled interval. When analyzed at the generic level, a statistically significant increase was observed for both Notharctus and Hyopsodus. Finally, a genus-level analysis of Orohippus showed a lack of statistically significant size increase over the study interval. Thus, among the three taxa from the Bridgerian, Bergmann’s Rule is supported by Notharctus and Hyopsodus, at least at the genus level, but not by Orohippus, although the patterns are more variable at the intraspecific level.
In Chapter 4, 40Ar/39Ar dates were obtained from sanidines from the middle Eocene Henrys Fork tuff and Upper Carboniferous Fire Clay tonstein, with the goal of making highly precise measurements of these two samples, keyed to the Fish Canyon monitor standard. Analytically, both samples were well characterized, as had been shown previously. The irradiation disk was arranged such that there would have been control from the Fish Canyon surrounding each of the unknown pits. However, due to several complications in the lab during the course of the experiment, only the analyses from one run disk (Disk 677) were of the quality needed for the goals of the study. As a result, the Fish Canyon sanidine standards that were irradiated near the center of the irradiation disk had to be discarded, and thus, the neutron fluence could not be mapped out precisely across the entire disk. The 40Ar/39Ar age relative to Fish Canyon sanidines is 47.828 ± 0.205 Ma and 311.937 ± 1.282 Ma for the Henrys Fork tuff and Fire Clay tonstein, respectively (1σ, including error on the age of the monitor). Because the ages were both offset about the same amount, I explored the option of using the U-Pb ID-TIMS ages of the Henrys Fork tuff and Fire Clay tonstein to test the agreement in the chronometers. The Henrys Fork tuff was dated at 48.260 ± 0.107 Ma (1σ, including error on the age of the monitor) using the Fire Clay sanidines and assuming its age is the U-Pb zircon age. The Fire Clay tonstein was dated at 314.593 ± 0.699 Ma (1σ, including error on the age of the monitor), using the Henrys Fork sanidines and assuming its age is the U/Pb zircon age. Although the complications encountered render these data unpublishable, they show great promise as the ages of each sanidine sample, tied to the other ash using the other ash’s U-Pb age, give results that are in close agreement between the two chronometers on the same sample (e.g., 314.593 ± 0.699 Ma vs. 314.554 ± 0.020 Ma at 1σ for sanidine and zircon respectively from the Fire Clay tonstein, and 48.260 ± 0.107 Ma vs. 48.265 ± 0.008 Ma 1σ for sanidine and zircon respectively from the Henrys Fork tuff).
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Schmidt, Rolf 1972. „Eocene bryozoa of the St Vincent Basin, South Australia - taxonomy, biogeography and palaeoenvironments“. 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phs3491.pdf.
Annotation:
Includes Publication list by the author as appendix A. "July 2003." Includes bibliographical references (leaves 308-324) A stratigraphically detailed taxonomic study of fossil bryozoans within the Late Eocene sediments of the St Vincent Basin, South Australia. These taxa are compared with existing knowledge of fossil and recent faunas in Australia and other regions to enhance understanding of bryozoan evolution and dispersal. Bryozoan taxa and growth forms are used to interpret the palaeoenvironments of the Eocene Vincent Basin.
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Schmidt, Rolf. „Eocene bryozoa of the St Vincent Basin, South Australia - taxonomy, biogeography and palaeoenvironments“. Thesis, 2003. http://hdl.handle.net/2440/22001.
Annotation:
Includes Publication list by the author as appendix A.Includes bibliographical references (leaves 308-324)
xi, 324, [36] leaves, 61 leaves of plates : ill (some col.), maps ; 30 cm.
A stratigraphically detailed taxonomic study of fossil bryozoans within the Late Eocene sediments of the St Vincent Basin, South Australia. These taxa are compared with existing knowledge of fossil and recent faunas in Australia and other regions to enhance understanding of bryozoan evolution and dispersal. Bryozoan taxa and growth forms are used to interpret the palaeoenvironments of the Eocene Vincent Basin.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2003?
41
Budiman, Indra. „Interpretation of gravity data over central Jawa, Indonesia“. Thesis, 1991. http://hdl.handle.net/2440/110285.
Annotation:
This thesis aims to establish the correlation between gravity data and volcanic structure in Central Jawa, Indonesia. The study provides information on the major boundary which separates the Eocene sediment in the south from the younger sediment in the north. The results of this research may offer a better understanding of the major structural elements of island arcs.Thesis (M.Sc.) -- University of Adelaide, Dept. of Geology and Geophysics, 1995?
42
Higinbotham, Larry R. „Stratigraphy, depositional history, and petrology of the Upper Cretaceous(?) to middle Eocene Montgomery Creek Formation, northern California /“. 1986. http://hdl.handle.net/1957/10678.
43
Ryu, In-Chang. „Stratigraphy, sedimentology, and hydrocarbon potential of Eocene forearc and subduction zone strata in the southern Tyee Basin, Oregon Coast Range“. Thesis, 1995. http://hdl.handle.net/1957/15259.
Annotation:
Thesis (Ph. D.)--Oregon State University, 1995.System requirements for computer disk: IBM-compatible PC. Typescript (photocopy). Includes plates in pocket. Includes bibliographical references. Also available on the World Wide Web.