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Letteratura scientifica selezionata sul tema "Geology, Stratigraphic Eocene"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 1 agosto 2024

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Articoli di riviste sul tema "Geology, Stratigraphic Eocene"

Birgenheier, L. P., M. D. Vanden Berg, P. Plink-Björklund, R. D. Gall, E. Rosencrans, M. J. Rosenberg, L. C. Toms e J. Morris. "Climate impact on fluvial-lake system evolution, Eocene Green River Formation, Uinta Basin, Utah, USA". GSA Bulletin 132, n. 3-4 (19 giugno 2019): 562–87. http://dx.doi.org/10.1130/b31808.1.

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Abstract In light of a modern understanding of early Eocene greenhouse climate fluctuations and new highly seasonal fluvial system faces models, the role of climate in the evolution of one classically-cited continental, terminal lake system is re-examined. Detailed stratigraphic description and elemental abundance data from fifteen cores and seven outcrop regions of the Green River Formation were used to construct a ∼150 km cross section across the Uinta Basin, Utah, USA. Lake Uinta in the Uinta Basin is divided into five lake phases: (1) post-Paleocene Eocene Thermal Maximum, (2) peak Eocene hyperthermal, (3) waning hyperthermal, Early Eocene Climatic Optimum (EECO), (4) post-hyperthermal, and (5) post-EECO regimes, based primarily on climatically driven changes in fluvial style in combination with sedimentary indicators of lacustrine carbonate deposition, organic matter preservation, salinity, and lake depth. Basinwide siliciclastic dominated intervals were deposited by highly seasonal fluvial systems and record negative organic carbon isotope excursions associated with early Eocene abrupt, transient global warming (hyperthermal) events. Carbonate dominated or organic rich intervals record stable, less seasonal climate periods between hyperthermals, with lower siliciclastic sediment supply allowing the development of carbonate and organic matter preservation. The stratigraphic progression from alternating organic rich and lean zones to the overlying organic rich Mahogany and R8 zones represents the global transition out of the pulsed early Eocene hyperthermal climate regime to a time of sediment starvation and lake stratification, sequestering sedimentary organic carbon. This study provides a novel approach to terrestrial paleoclimate reconstruction that relies largely on unique sedimentary indicators and secondarily on isotopic proxy records within the context of a large basin-wide sedimentologic and stratigraphic data set, thus setting the stage for future detailed geochemical terrestrial paleoclimate proxy development.

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Reinhardt, Lutz, Werner von Gosen, Andreas Lückge, Martin Blumenberg, Jennifer M. Galloway, Christopher K. West, Markus Sudermann e Martina Dolezych. "Geochemical indications for the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM-2) hyperthermals in terrestrial sediments of the Canadian Arctic". Geosphere 18, n. 1 (7 gennaio 2022): 327–49. http://dx.doi.org/10.1130/ges02398.1.

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Abstract During the late Paleocene to early Eocene, clastic fluvial sediments and coals were deposited in northern high latitudes as part of the Margaret Formation at Stenkul Fiord (Ellesmere Island, Nunavut, Canada). Syn-sedimentary tectonic movements of the Eurekan deformation continuously affected these terrestrial sediments. Different volcanic ash layers occur, and unconformities subdivide the deposits into four sedimentary units. Rare vertebrate fossils indicate an early Eocene (Graybullian) age for the upper part of the Stenkul Fiord outcrop. Here, we present carbon isotope data of bulk coal, related organic-rich mud and siltstones, a plant leaf wax-derived alkane, and additional plant remains. These data provide a complete carbon isotope record of one stratigraphic section with defined unconformity positions and in relation to other Eurekan deformation features. A previously dated ash layer MA-1 provided a U-Pb zircon age of 53.7 Ma and is used as a stratigraphic tie point, together with a discrete negative carbon isotope excursion found above MA-1 in a closely sampled coal seam. The excursion is identified as the likely expression of the I-1 hyperthermal event. Based on our isotope data that reflect the early Eocene dynamics of the carbon cycle, this tie point, and previous paleontological constraints from vertebrate fossils, the locations of the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM-2) hyperthermals and their extent along the complete section are herein identified. Within the intervals of the PETM and ETM-2 hyperthermal events, increasing amounts of clastic sediments reached the site toward the respective end of the event. This is interpreted as a response of the fluvial depositional system to an intensified hydrological system during the hyperthermal events. Our study establishes an enhanced stratigraphic framework allowing for the calculation of average sedimentation rates of different intervals and considerations on the completeness of the stratigraphic record. As one of the few high-latitude outcrops of early Eocene terrestrial sediments, the Stenkul Fiord location offers further possibilities to study the effects of extreme warming events in the Paleogene.

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Higgs, Karen E., Stuart Munday, Anne Forbes, Erica M. Crouch e Matthew W. Sagar. "A geochemical and biostratigraphic approach to investigating regional changes in sandstone composition through time; an example from Paleocene–Eocene strata, Taranaki Basin, New Zealand". Geological Magazine 157, n. 9 (17 febbraio 2020): 1473–98. http://dx.doi.org/10.1017/s0016756819001596.

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AbstractA geochemical and biostratigraphic approach has been applied to investigate the spatial and stratigraphic variability of Palaeogene sandstones from key wells in Taranaki Basin, New Zealand. Chronostratigraphic control is predominantly based on miospore zonation, while differences in the composition of Paleocene and Eocene sandstones are supported by geochemical evidence. Stratigraphic changes are manifested by a significant decrease in Na2O across the New Zealand miospore PM3b/MH1 early Eocene zonal boundary, at approximately 53.5 Ma. The change in Na2O is associated with a decrease in baseline concentrations of many other major (MnO, CaO, TiO2) and trace elements, and is interpreted to reflect a significant change in sandstone maturity. Paleocene sandstones are characterized by abundant plagioclase (albite and locally Na–Ca plagioclase), significant biotite and a range of heavy minerals, while Eocene sandstones are typically quartzose, with K-feldspar dominant over plagioclase, low mica contents and rare heavy minerals comprising a resistant suite. This change could reflect a change in provenance from local plutonic basement during the Paleocene Epoch to relatively quartz- and K-feldspar-rich granitic sources during Eocene time. However, significant quartz enrichment of Eocene sediment was also likely due to transportation reworking/winnowing along the palaeoshoreface and enhanced chemical weathering, driven in part by long-term global warming associated with the Early Eocene Climatic Optimum. The broad-ranging changes in major-element composition overprint local variations in sediment provenance, which are only detectable from the immobile trace-element geochemistry.

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Siyako, M., e O. Huvaz. "Eocene stratigraphic evolution of the Thrace Basin, Turkey". Sedimentary Geology 198, n. 1-2 (maggio 2007): 75–91. http://dx.doi.org/10.1016/j.sedgeo.2006.11.008.

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Carraro, Davide, Dario Ventra e Andrea Moscariello. "Anatomy of a fluvial paleo-fan: sedimentological and architectural trends of the Paleocene–Eocene Wasatch–Colton System (western Uinta Basin, Utah, U.S.A.)". Journal of Sedimentary Research 93, n. 6 (30 giugno 2023): 370–412. http://dx.doi.org/10.2110/jsr.2022.095.

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ABSTRACT Recent developments in fluvial geomorphology and sedimentology suggest that fluvial fans (also known as distributive fluvial systems) could be responsible for the accumulation of great volumes of clastic successions in continental basins. A general depositional model based on sedimentological and architectural trends has been formulated for these fluvial systems, however, their recognition in the stratigraphic record often relies on partially preserved, discontinuous successions. This study provides a sedimentological and architectural characterization of Paleogene alluvial strata of the Wasatch and Colton formations in the southwestern Uinta Basin, central Utah (U.S.A.), following an ∼ 120-km-long outcrop belt which records deposition from an alluvial wedge that prograded to the north and northwest, from the basin margin to distal lake-dominated environments, preceding the onset of ancient Lake Uinta. Lateral and vertical distribution of facies associations are presented from a dataset of field observations (thirteen logged stratigraphic sections, for a total of ∼ 2400 m) and virtual outcrop models along the proximal-to-distal extent of the Wasatch–Colton alluvial system. Four sectors are defined (proximal, medial, distal, and terminal) to mark the longitudinal heterogeneity of alluvial stratigraphy. Noteworthy trends comprise a downstream decrease in the overall thickness of the alluvial stratigraphic column, a reduction in the relative volume, architectural complexity, and amalgamation of fluvial-channel bodies away from the apex, a weak downstream-fining trend in channel sandstones, and a down-system increase in preserved overbank and floodplain deposits accompanied by increasing volume and facies complexity of preserved lacustrine and palustrine facies associations. A proximal-to-distal change in fluvial-channel architecture is noted, with proximal sections characterized by vertically and laterally amalgamated sheet-like channel fills, transitioning to a lesser degree of amalgamation towards the medial sector, whereas distal and terminal sections are dominated by floodplain fines enveloping a subordinate volume of isolated, ribbon-shaped channel-sandstone bodies. The temporal development of the stratigraphic succession is observed in its entirety throughout the field area and, albeit localized, channel-scale erosion and potential depositional hiatuses punctuate the stratigraphy. Two major system-scale trends have been described in the Wasatch–Colton System (WCS). A first-order, long-term progradational trend, especially evident in proximal and medial sections, encompasses the large-scale vertical patterns in facies and architecture vertically through most of the stratigraphy of the WCS. In contrast, the uppermost part of the stratigraphic succession is characterized by a reverse, retrogradational trend, possibly associated with the early transgression of Lake Uinta's southern margin, marking the base of the overlying Green River Formation. Albeit expressed by different vertical succession of facies, proximal-to-distal processes, and stratal patterns documented along a longitudinal transect of the WCS mirror substantially identical vertical trends through the stratigraphy, which are interpreted as Waltherian superposition of distinct depositional domains during fluvial-fan progradation. Analyses of sandstone petrography and zircon geochronology suggest a unified source for the fluvial system, also supporting an interpretation as a distributive, rather than a tributive, fluvial system. This study enhances our understanding of the current depositional model for extensive fluvial-fan successions via a regional-scale stratigraphic analysis of a fluvial paleo-fan based on integrated characterization of both vertical and down-system patterns in facies distribution and fluvial architecture, providing key insights on useful criteria for recognizing fluvial-fan successions from the rock record.

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Galeotti, Simone, Eugenia Angori, Rodolfo Coccioni, Gabriella Ferrari, Bruno Galbrun, Simonetta Monechi, Isabella Premoli Silva, Robert Speijer e Bruno Turi. "Integrated stratigraphy across the Paleocene/Eocene boundary in the Contessa Road section, Gubbio (central Italy)". Bulletin de la Société Géologique de France 171, n. 3 (1 maggio 2000): 355–65. http://dx.doi.org/10.2113/171.3.355.

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Abstract An integrated stratigraphic study of the upper Paleocene to lower Eocene Scaglia limestones of the Contessa Road section has allowed us to identify the classical markers of the Paleocene-Eocene transition. The section provides a good magnetostratigraphic record as well as a continuous calcareous nannofossil and foraminiferal biostratigraphy. A negative Carbon Isotopic Excursion (CIE) occurs in the lower part of Chron C24r. The calibration to calcareous plankton zonation indicates that the CIE occurs in the lowermost part of calcareous nannofossil Zone NP10 and the upper part of Zone CP8, that is in the planktonic foraminiferal Zone P5. In the same stratigraphic interval, a distinct turnover in the calcareous benthic foraminifera and a sharp change in the Deep Water Agglutinated Foraminiferal (DWAF) assemblages have been recognised. The record of DWAF, however, indicates a gradual initiation of such a change beginning some 150 k.y. before the CIE and BEE.

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Riddell, Janet. "Lithostratigraphic and tectonic framework of Jurassic and Cretaceous Intermontane sedimentary basins of south-central British Columbia1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia." Canadian Journal of Earth Sciences 48, n. 6 (giugno 2011): 870–96. http://dx.doi.org/10.1139/e11-034.

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The south-central Intermontane belt of British Columbia has a complex architecture comprising late Paleozoic to Mesozoic volcanic and plutonic arc magmatic suites, marine and nonmarine clastic basins, high-grade metamorphic complexes, and accretionary rocks. Jurassic and Cretaceous clastic basins within this framework contain stratigraphy with hydrocarbon potential. The geology is complicated by Cretaceous to Eocene deformation, dismemberment, and dislocation. The Eocene to Neogene history of the southern Intermontane belt is dominated by non-arc volcanism, followed by Pleistocene to Recent glaciation. The volcanic and glacial cover makes this a difficult region to explore for resources. Much recent work has involved re-evaluating the challenges that the overlying volcanic cover has historically presented to geophysical imaging of the sedimentary rocks in this region in light of technological advances in geophysical data collection and analysis. This paper summarizes the lithological and stratigraphic framework of the region, with emphasis on description of the sedimentary units that have been the targets of hydrocarbon exploration.

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Nielsen, Jan Kresten. "Commensal association of Corbula gibba (Bivalvia) and a sub-conical boring". Bulletin of the Geological Society of Denmark 45 (30 gennaio 1999): 135–38. http://dx.doi.org/10.37570/bgsd-1998-45-15.

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An examination of fossil and Recent right valves of the infaunal, suspensionfeeding Corbula gibba (Olivi, 1792) revealed the presence of a slender, sub- conical, unbranched boring. The boring is interpreted as the work of a commensal organism, possible a parasite. Stratigraphic range is from Eocene to Recent.

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Pomerol, Charles. "Limites evenementielles ou limites conventionnelles en stratigraphie?" Bulletin de la Société Géologique de France IV, n. 2 (1 marzo 1988): 357–60. http://dx.doi.org/10.2113/gssgfbull.iv.2.357.

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Abstract Most events characterising stratigraphic boundaries span an interval of time. The boundaries are often diachronous and they may be affected by environmental conditions. Therefore, the only accurate way to define a boundary is to select a boundary stratotype which records as many paleontological, geophysical and geochemical events as possible. Conventional stratigraphic boundaries are commonly difficult to identify precisely outside the stratotype area. This is why it is necessary to use first and last appearances of diagnostic features which occur below and above the conventional boundary. In this point of view the Eocene-Oligocene boundary is particularly significant.

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Rasmussen, Dirk M., Brady Z. Foreman, Henry C. Fricke, Kathryn Snell, Lindsey Gipson e Bernard Housen. "The early Paleogene stratigraphic evolution of the Huerfano Basin, Colorado". Rocky Mountain Geology 55, n. 1 (1 luglio 2020): 1–26. http://dx.doi.org/10.24872/rmgjournal.55.1.1.

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ABSTRACT Sedimentary basins throughout the North American Western Interior contain a record of Late Cretaceous through Eocene deposition related to the Laramide orogeny. The typical stratigraphic progression includes an uppermost Cretaceous fluvio-deltaic geologic formation that is unconformably overlain by an alluvial or paludal Paleocene geologic formation. The Paleocene unit is usually characterized by drab overbank facies, and overlain by an interval of amalgamated fluvial sand bodies. The overlying Eocene geologic units are characterized by red bed overbank facies. These major stratigraphic changes have been variably linked to long-wavelength dynamic subsidence, local uplift, and climatic shifts. Herein, we evaluate the depositional history of the Huerfano Basin of south-central Colorado in this overarching context. Our study presents a detailed lithofacies analysis of the Poison Canyon, Cuchara, and Huerfano Formations integrated with a new bulk (1) organic carbon isotope record, n = 299 measurements (Data Supplement 1A); and (2) magnetic record, n = 247 measurements (Data Supplement 1B). We interpret that the Paleocene Poison Canyon Formation was deposited by a braided or coarse-grained meandering river system with relatively poorly drained floodplains. The Eocene Huerfano Formation was likely deposited by a coarse-grained meandering river system with a comparatively well-drained floodplain. This pattern mirrors other Laramide basins, and is likely related to a regional drying pattern linked to long-term warming during the early Paleogene. Age of the intervening Cuchara Formation is poorly resolved, but is an anomalously thick and coarse-grained fluvial unit, with evidence for extensive reworking of floodplain deposits and a moderate coarsening-upward pattern. The Cuchara Formation is associated with magnetic trends that suggest greater oxidation and weathering, and greater variability in rainfall patterns, as well as a subtle negative shift in carbon isotope values. This pattern indicates a period of widespread progradation within the basin, potentially related to a major Laramide uplift event that affected Colorado’s Wet Mountains, Front Range, and Sangre de Cristo Mountains.

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Più fonti

Tesi sul tema "Geology, Stratigraphic Eocene"

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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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).

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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.

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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.

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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.

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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.

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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.

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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

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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.

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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

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Più fonti

Libri sul tema "Geology, Stratigraphic Eocene"

R, Prothero Donald, e Berggren William A, a cura di. Eocene-Oligocene climatic and biotic evolution. Princeton, N.J: Princeton University Press, 1992.

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Huddlestun, Paul F. Upper eocene stratigraphy of central and eastern Georgia. Atlanta: Dept. of Natural Resources, Environmental Protection Division, Georgia Geologic Survey, 1986.

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Zágoršek, Kamil. Eocene bryozoa from Hungary. Frankfurt am Main: Senckenbirgische Naturforschende Gesellschaft, 2001.

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Hall, Wayne Everett. Eocene cauldron, batholith, and hydrothermal alteration west of Ketchum, Idaho. [Reston, Va.?]: U.S. Dept. of the Interior, Geological Survey, 1986.

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Roehler, Henry W. Description and correlation of Eocene rocks in stratigraphic reference sections for the Green River and Washakie basins, Southwest Wyoming : includes analyses of Eocene rocks in the Washakie Basin. Washington: U.S. G.P.O., 1992.

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Johnson, Samuel Y. Stratigraphy, sedimentology, and provenance of the Raging River Formation (Early? and Middle Eocene), King County, Washington. Washington: U.S. G.P.O., 1994.

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Roehler, Henry W. Correlation, composition, areal distribution, and thickness of Eocene stratigraphic units, greater Green River Basin, Wyoming, Utah, and Colorado. [Reston, Va.?]: U.S. Dept. of the Interior, U.S. Geological Survey, 1992.

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Thorson, Jon P. Geology of upper Cretaceous, Paleocene and Eocene strata in the southwestern Denver Basin, Colorado. Denver, Colo: Colorado Geological Survey, Department of Natural Resources, 2011.

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Squires, Richard L. Paleontology and stratigraphy of Eocene rocks at Pulali Point, Jefferson County, eastern Olympic Peninsula, Washington. [Olympia, Wash.]: Washington State Dept. of Natural Resources, Division of Geology and Earth Resources, 1992.

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Bybell, Laurel M. The Eocene Tallahatta Formation of Alabama and Georgia: Its lithostratigraphy, biostratigraphy, and bearing on the age of the Claibornian stage. Washington: U.S. G.P.O., 1985.

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Capitoli di libri sul tema "Geology, Stratigraphic Eocene"

AlRefaei, Yaqoub, Ali Najem, Aimen Amer e Faisal Al-Qattan. "Surface Geology of Kuwait". In The Geology of Kuwait, 1–26. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-16727-0_1.

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AbstractThis chapter represents a comprehensive review of Kuwait’s surface geology and stratigraphy from previous works accomplished by numerous geoscience researchers in the past decades. The surface of Kuwait is characterized by nearly flat topography, featureless to gently undulating, apart from a few tens of meters of escarpments in the north and south, and flat low to moderately elevated hills and ridges. It predominantly consists of siliciclastic sediments and sedimentary rock units ranging in age from Middle Eocene to Holocene. The main stratigraphic exposed successions are located in Jal Az-Zor escarpment, Al-Subyiah (Bahrah) area, Ahmadi Quarry, the Khiran Ridges, and the Enjefa Beach. The oldest exposed rock units are represented by the Middle Eocene Dammam Formation, which is exposed at the Ahmadi Quarry, whereas the youngest recent deposits cover most of Kuwait’s surficial area and lie on top of the Kuwait Group’s deposits. This chapter will illustrate the geology and stratigraphy of Kuwait's surface sediments and sedimentary rock strata. Recommendations and future insights were also documented as part of the way forward to improve the presently available work for the surface geology of Kuwait.

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Śliwinska, Kasia K., Stefan Schouten e Karen Dybkjær. "Lower Eocene to Lower Miocene Stratigraphy and Palaeoenvironment of ODP Site 643A, Norwegian Sea". In Springer Geology, 143–47. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-04364-7_29.

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Schofield*, Glen J., e Chad J. Pritchard. "Paleontology, stratigraphy, and structural features of the lower bedded member of the Metaline Formation, Lafarge quarry, Metaline Falls, Washington, USA". In Proterozoic Nuna to Pleistocene Megafloods: Sharing Geology of the Inland Northwest, 59–66. Geological Society of America, 2024. http://dx.doi.org/10.1130/2024.0069(03).

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ABSTRACT This one-day field trip of regional geologic significance goes from Spokane, Washington, north along the Pend Oreille River to the Lafarge limestone quarries in the Metaline Formation near Metaline Falls, Washington, USA. Along the way, we will discuss local geologic and geomorphic features, archaeology of the Native culture, features of Pleistocene glaciation and the Eocene Newport fault in the Pend Oreille valley, and highlights of roadcuts and rock types. The main focus of the field trip centers on the paleontology of the lower bedded member of the Metaline Formation in the Lafarge quarry. Based on recent fossil identification of recently discovered trilobites, the age of the lower bedded member has been refined to Series 2-Stage 4 of the Cambrian. We will examine potential new species at stopping points within the quarry, identify key units of stratigraphy and relate them to the stratigraphic column of the guide, and include a structural geology discussion. Deformed trilobites, cleavage, and calcite-filled fractures indicate NW-SE compression during Mesozoic Cordilleran tectonism.

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Vaughan, Jeremy, Carl E. Nelson, Guillermo Garrido, Jose Polanco, Valery Garcia e Arturo Macassi. "Chapter 20: The Pueblo Viejo Au-Ag-Cu-(Zn) Deposit, Dominican Republic". In Geology of the World’s Major Gold Deposits and Provinces, 415–30. Society of Economic Geologists, 2020. http://dx.doi.org/10.5382/sp.23.20.

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Abstract The world-class Pueblo Viejo Au deposit in the central Dominican Republic is one of the largest high-sulfidation epithermal Au deposits globally, with past production plus resources and reserves of 41.7 million ounces (Moz) in the Moore and Monte Negro deposits. Mineralization occurs within a 2- × 2-km Early Cretaceous volcano-sedimentary basin filled with felsic volcanic and volcaniclastic rocks, interlayered carbonaceous sedimentary units, and underlying andesitic flows and tuffs. The volcanic stratigraphy was developed during a period of tholeiitic magmatism that transitioned to calc-alkaline magmatism at the time of emplacement of the late- to postmineral Monte Negro dike (~109 Ma). Additional geologic controls to mineralization include high-angle, NE- and NW-faulting, phreatomagmatic breccias, and possible volcanic domes. Mineralization is present across the stratigraphic sequence, with mineralization at Moore dominantly hosted within quartz-bearing volcaniclastic rocks and overlying carbonaceous sedimentary units, whereas that at Monte Negro is in the andesitic sequence as well as overlying epiclastic and sedimentary units. Alteration at the shallowest level is dominated by quartz-pyrophyllite, whereas alunite alteration defines the deep roots to the ore-forming environment. Mineralization comprises early disseminated-type and late veins filled with pyrite ± sphalerite. Hypogene ore is refractory in nature, with Au in solid solution or as mineral inclusions within arsenian pyrite. Re-Os ages of 113.4 ± 2.6 Ma for auriferous pyrite along with new geologic observations appear to confirm an Early Cretaceous age for mineralization, although Re-Os enargite ages suggest the possibility of a second mineralization event in the Eocene.

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Bradley, Mark A., L. Page Anderson, Nathan Eck e Kevin D. Creel. "Chapter 16: Giant Carlin-Type Gold Deposits of the Cortez District, Lander and Eureka Counties, Nevada". In Geology of the World’s Major Gold Deposits and Provinces, 335–53. Society of Economic Geologists, 2020. http://dx.doi.org/10.5382/sp.23.16.

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Abstract The Cortez district is in one of the four major Carlin-type gold deposit trends in the Great Basin province of Nevada and contains three giant (>10 Moz) gold orebodies: Pipeline, Cortez Hills, and Goldrush, including the recently discovered Fourmile extension of the Goldrush deposit. The district has produced >21 Moz (653 t) of gold and contains an additional 26 Moz (809 t) in reserves and resources. The Carlin-type deposits occur in two large structural windows (Gold Acres and Cortez) of Ordovician through Devonian shelf- and slope-facies carbonate rocks exposed through deformed, time-equivalent lower Paleozoic siliciclastic rocks of the overlying Roberts Mountains thrust plate. Juxtaposition of these contrasting Paleozoic strata occurred during the late Paleozoic Antler orogeny along the Roberts Mountains thrust. Both upper and lower plate sequences were further deformed by Mesozoic compressional events. Regional extension, commencing in the Eocene, opened high- and low-angle structural conduits for mineralizing solutions and resulted in gold deposition in reactive carbonate units in structural traps, including antiforms and fault-propagated folds. The Pipeline and Cortez Hills deposits are located adjacent to the Cretaceous Gold Acres and Jurassic Mill Canyon granodioritic stocks, respectively; although these stocks are genetically unrelated to the later Carlin-type mineralization event, their thermal metamorphic aureoles may have influenced ground preparation for later gold deposition. Widespread decarbonatization, argillization, and silicification of the carbonate host rocks accompanied gold mineralization, with gold precipitated within As-rich rims on fine-grained pyrite. Pipeline and Cortez Hills also display deep supergene oxidation of the hypogene sulfide mineralization. Carlin-type mineralization in the district is believed to have been initiated in the late Eocene (>35 Ma) based on the age of late- to postmineral rhyolite dikes at Cortez Hills. The Carlin-type gold deposits in the district share common structural, stratigraphic, alteration, and ore mineralogic characteristics that reflect common modes of orebody formation. Ore-forming fluids were channeled along both low-angle structures (Pipeline, Goldrush/Fourmile) and high-angle features (Cortez Hills), and gold mineralization was deposited in Late Ordovician through Devonian limestone, limy mudstone, and calcareous siltstone. The Carlin-type gold fluids are interpreted to be low-salinity (2–3 wt % NaCl equiv), low-temperature (220°–270°C), and weakly acidic, analogous to those in other Carlin-type gold deposits in the Great Basin. The observed characteristics of the Cortez Carlin-type gold deposits are consistent with the recently proposed deep magmatic genetic model. Although the deposits occur over a wide geographic area in the district, it is possible that they initially formed in greater proximity to each other and were then spatially separated during Miocene and post-Miocene regional extension.

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Sullivan, Raymond, Morgan D. Sullivan, Stephen W. Edwards, Andrei M. Sarna-Wojcicki, Rebecca A. Hackworth e Alan L. Deino. "Mid-Cenozoic succession on the northeast limb of the Mount Diablo anticline, California—A stratigraphic record of tectonic events in the forearc basin". In Regional Geology of Mount Diablo, California: Its Tectonic Evolution on the North America Plate Boundary. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.1217(13).

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ABSTRACT The mid-Cenozoic succession in the northeast limb of the Mount Diablo anticline records the evolution of plate interactions at the leading edge of the North America plate. Subduction of the Kula plate and later Farallon plate beneath the North America plate created a marine forearc basin that existed from late Mesozoic to mid-Cenozoic times. In the early Cenozoic, extension on north-south faults formed a graben depocenter on the west side of the basin. Deposition of the Markley Formation of middle to late? Eocene age took place in the late stages of the marine forearc basin. In the Oligocene, the marine forearc basin changed to a primarily nonmarine basin, and the depocenter of the basin shifted eastward of the Midland fault to a south-central location for the remainder of the Cenozoic. The causes of these changes may have included slowing in the rate of subduction, resulting in slowing subsidence, and they might also have been related to the initiation of transform motion far to the south. Two unconformities in the mid-Cenozoic succession record the changing events on the plate boundary. The first hiatus is between the Markley Formation and the overlying Kirker Formation of Oligocene age. The succession above the unconformity records the widespread appearance of nonmarine rocks and the first abundant appearance of silicic volcanic detritus due to slab rollback, which reversed the northeastward migration of the volcanic arc to a more proximal location. A second regional unconformity separates the Kirker/Valley Springs formations from the overlying Cierbo/Mehrten formations of late Miocene age. This late Miocene unconformity may reflect readjustment of stresses in the North America plate that occurred when subduction was replaced by transform motion at the plate boundary. The Cierbo and Neroly formations above the unconformity contain abundant andesitic detritus due to proto-Cascade volcanism. In the late Cenozoic, the northward-migrating triple junction produced volcanic eruptive centers in the Coast Ranges. Tephra from these local sources produced time markers in the late Cenozoic succession.

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Sullivan, Raymond, Ryan P. Fay, Carl Schaefer, Alan Deino e Stephen W. Edwards. "Neogene volcanism on the eastside of Mount Diablo, Contra Costa County, California". In Regional Geology of Mount Diablo, California: Its Tectonic Evolution on the North America Plate Boundary. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.1217(11).

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ABSTRACT Two spatially separated areas of Neogene volcanic rocks are located on the northeast limb of the Mount Diablo anticline. The southernmost outcrops of volcanics are 6 km east of the summit of Mount Diablo in the Marsh Creek area and consist of ~12 hypabyssal dacite intrusions dated at ca. 7.8–7.5 Ma, which were intruded into the Great Valley Group of Late Cretaceous age. The intrusions occur in the vicinity of the Clayton and Diablo faults. The rocks are predominantly calc-alkaline plagioclase biotite dacites, but one is a tholeiitic plagioclase andesite. Mercury mineralization was likely concomitant with emplacement of these late Miocene intrusions. The northern most outcrops of Neogene volcanic rocks occur ~15 km to the north of Mount Diablo in the Concord Naval Weapons Station and the Los Medanos Hills and are probably parts of a single andesite flow. A magnetometer survey indicates that the flow originated from a feeder dike along the Clayton fault. The lava flow is flat-lying and occu pies ancient stream channels across an erosional surface of tilted Markley Sandstone of middle Eocene age. New radiometric dates of the flow yield an age of 5.8–5.5 Ma, but due to alteration the age should be used with caution. The flow is a calc-alkaline andesite rich in clinopyroxene and plagioclase. What appear to be uplifted erosional remnants of the flow can be traced northeastward in the Los Medanos Hills across a surface of tilted Cenozoic rocks that eventually rest on formations as young as the Lawlor Tuff dated at 4.865 ± 0.011 Ma. This stratigraphic relationship suggests that the andesite flow is probably late Pliocene in age and was impacted by the more recent uplift of the Los Medanos Hills but postdates the regional folding and faulting of the rocks of Mount Diablo. In terms of timing, location, and composition, the evidence suggests these two areas of dacitic and andesitic volcanics fit into a series of migrating volcanic centers in the California Coast Ranges that erupted following the northward passage of the Mendocino Triple Junction.

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Armentrout, John M. "Tectonics and paleogeography of a post-accretionary forearc basin, Coos Bay area, SW Oregon, USA". In From Terranes to Terrains: Geologic Field Guides on the Construction and Destruction of the Pacific Northwest, 187–243. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.0062(06).

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ABSTRACT This field guide reviews 19 sites providing insight to four Cenozoic deformational phases of the Cascadia forearc basin that onlaps Siletzia, an oceanic basaltic terrane accreted onto the North American plate at 51–49 Ma. The field stops visit disrupted slope facies, prodelta-slope channel complexes, shoreface successions, and highly fossiliferous estuarine sandstones. New detrital zircon U-Pb age calibration of the Cenozoic formations in the Coos Bay area and the Tyee basin at-large, affirm most previous biostratigraphic correlations and support that some of the upper-middle Eocene to Oligocene strata of the Coos Bay stratigraphic record represents what was differentially eroded off the Coast Range crest during ca. 30–25 Ma and younger deformations. This suggests that the strata along Cape Arago are a western “remnant” of the Paleogene Tyee basin. Zircon ages and biostratigraphic data encourages the extension of the Paleogene Coos Bay and Tyee forearc basin westward beyond the Fulmar fault and offshore Pan American and Fulmar wells. Integration of outcrop paleocurrents with anisotropy of magnetic susceptibility data from the middle Eocene Coaledo Formation affirms south-southeast to north-northwest sediment transport in current geographic orientation. Preliminary detrital remanent magnetism data show antipodal directions that are rotated clockwise with respect to the expected Eocene field direction. The data suggest the Eocene paleo-shoreline was relatively north-south similar to the modern shoreline, and that middle Eocene sediment transport was to the west in the area of present-day Coos Bay. A new hypothesis is reviewed that links the geographic isolation of the Coos Bay area from rivers draining the ancestral Cascades arc to the onset of uplift of the southern Oregon Coast Range during the late Oligocene to early Miocene.

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"EARLY EOCENE (YPRESIAN) CALCAREOUS NANNOFOSSIL STRATIGRAPHY FROM THE CARIBBEAN REGION OF COLOMBIA, SOUTH AMERICA". In GEOLOGIC PROBLEM SOLVING WITH MICROFOSSILS IV, 161–71. Society for Sedimentary Geology, 2019. http://dx.doi.org/10.2110/sepmsp.111.07.

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Gaillot*, Gwladys T., Michael L. Sweet e Manasij Santra. "Deep-water deposits of the Eocene Tyee Formation, Oregon". In From Terranes to Terrains: Geologic Field Guides on the Construction and Destruction of the Pacific Northwest, 19–48. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.0062(02).

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ABSTRACT The Eocene Tyee Formation of west central Oregon, USA, records deposition in a forearc basin. With outcrop exposures of fluvial/deltaic to shelf and submarine fan depositional environments and known sediment sourcing constrained by detrital zircon dating and mineralogy linked to the Idaho Batholith, it is possible to place deposits of the Tyee Formation in a source-to-sink context. A research program carried out by the Department of Geological Sciences at The University of Texas at Austin and ExxonMobil Research Company’s Clastic Stratigraphy Group has reconstructed the Eocene continental margin from shelf to slope to basin floor using outcrop and subsurface data. This work allows us to put observations of individual outcrops into a basin-scale context. This field trip will visit examples of depositional environments across the entire preserved source-to-sink system, but it will focus on the deep-water deposits of the Tyee Formation that range from slope channels to proximal and distal basin-floor fans. High-quality roadcuts reveal the geometry of slope channel-fills in both depositional strike and dip orientations. Thick, sand-rich medial fan deposits show vertical amalgamation and a high degree of lateral continuity of sandstones and mudstones. Distal fan facies with both classic Bouma-type turbidites and combined flow or slurry deposits are well exposed along a series of new roadcuts east of Newport, Oregon. The larger basin-scale context of the Tyee Formation is illustrated at a quarry in the northern end of the basin where the contact between the oceanic crust of the underlying Siletzia terrane and submarine fan deposits of the Tyee Formation is exposed. The Tyee Formation provides an excellent opportunity to see the facies and three-dimensional geometry of deep-water deposits, and to show how these deposits can be used to help reconstruct ancient continental margins.

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Atti di convegni sul tema "Geology, Stratigraphic Eocene"

Utomo, R. "Unlocking The Complex Geology & Petroleum Systems; Efforts to Awakening The Sleeping Giant – A Prospectivity Rejuvenation Case Study of West Sebuku Block, South Makassar Basin, Indonesia". In Indonesian Petroleum Association 44th Annual Convention and Exhibition. Indonesian Petroleum Association, 2021. http://dx.doi.org/10.29118/ipa21-g-25.

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Significant uplift in the seismic imaging quality from the latest wide coverage of the Multi-Client Broadband PSDM 3D (MC3D) acquisition and processing, as well as cost and operational efficiencies, is an essential element to unlock the exploration potential of the under-explored South Makassar Basin. Many of exploration wells are usually drilled based on limited data, and structural closures are defined by sparse 2D seismic data and inadequate petroleum system models. Additional 3D seismic acquisition over the same area may enhance the structural imaging and provide a better understanding of the petroleum system. However, imaging the stratigraphic and structural complexities beneath carbonate platforms and steep slopes can be challenging and continued de-risk the plays. In 2018, Mubadala Petroleum requested PGS to acquire the first Multi-Client Broadband PSDM 3D survey in the South Makassar Basin. This MC3D survey has, for the first time, enabled imaging of well developed Eocene Platform carbonates and the Basement. Historical exploration and production activities with in the Basin have focused largely on the Oligocene aged carbonate debris flow deposits, as seen at Ruby Field. These new Eocene Platform carbonate and Basement plays have enabled Mubadala Petroleum to develop a significant exploration portfolio, revitalizing exploration activity in the Basin.

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Pitibhabhong, Tanporn, Rupam Chakraborty, Seng Hor Ng, Chee Kiong Lim, Ian Paton e Namfon Phantawee. "Advanced Multiple Attenuation and Model Building Techniques Provide New Insights Into the Jurassic Play of Timor sea, Offshore Australia". In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22780-ea.

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Abstract The Sandalford area, located in Australia’s northwestern continental margin, is proximal to the Cash-Maple and Tenacious field discoveries. The area has Eocene-Paleocene Carbonates overlying siliciclastic Cretaceous section, resulting in a strong velocity inversion as well as generating complex free-surface and internal-multiple contaminations at the deeper Jurassic reservoir section. We present a reprocessing case study of a narrow-azimuth, towed-streamer seismic dataset acquired in shallow water using advanced multiple attenuation and earth model building techniques, with the main goal of improving our understanding of the complex geology beneath. The multiple attenuation part of the workflow employs a cascaded approach, initially addressing water-layer multiples, remaining free-surface multiples, and followed with internal multiples. Implementation of high-frequency visco-acoustic full-waveform inversion (Q-FWI) improved the overburden velocity model and combined with effective multiple attenuation algorithms, reduced the uncertainty of primary events in the pre-carbonate section, therefore reducing errors in common image point (CIP) tomography. The results were quality-controlled against the well data, providing new insights with improved structural and stratigraphic delineation.

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Saraswati, Pratul Kumar, Sonal Khanolkar, D. S. N. Raju e Santanu Banerjee. "An Updated Eocene Stratigraphy of Kutch". In Recent Studies on the Geology of Kachchh. Geological Society of India, 2016. http://dx.doi.org/10.17491/cgsi/2016/105406.

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Almasinia, B., S. Ali Moallemi, F. Fürsich e M. Ahmad Hosseini. "Strontium Isotope Stratigraphy at Middle Eocene from the Zagros Mountains of Iran". In Sixth Arabian Plate Geology Workshop. Netherlands: EAGE Publications BV, 2016. http://dx.doi.org/10.3997/2214-4609.201602391.

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Meddaugh, William Scott, Dennis Dull, Raymond garber, Stewart Griest e David Lee Barge. "The Wafra First Eocene Reservoir Partitioned Neutral Zone (PNZ), Saudi Arabia and Kuwait: Geology, Stratigraphy, and Static Modeling". In SPE Middle East Oil and Gas Show and Conference. Society of Petroleum Engineers, 2007. http://dx.doi.org/10.2118/105087-ms.

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Rapporti di organizzazioni sul tema "Geology, Stratigraphic Eocene"

Anderson, Zachary W., Greg N. McDonald, Elizabeth A. Balgord e W. Adolph Yonkee. Interim Geologic Map of the Browns Hole Quadrangle, Weber and Cache Counties, Utah. Utah Geological Survey, dicembre 2023. http://dx.doi.org/10.34191/ofr-760.

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The Browns Hole quadrangle is in Weber and Cache Counties of northern Utah and covers the eastern part of Ogden Valley, a rapidly developing area of the Wasatch Range. The Middle and South Forks of the Ogden River bisect the quadrangle and are important watersheds and recreational areas to the communities of Ogden Valley and the Wasatch Front. The towns of Huntsville and Eden are just west of the quadrangle, unincorporated communities with year-round residents are present throughout the quadrangle, and numerous summer-cabin communities are present in the eastern part of the quadrangle. A portion of Powder Mountain ski resort, which draws year-round visitation and recreation, is present in the northwest corner of the quadrangle. The quadrangle contains the Willard thrust, a major thrust fault with approximately 30 mi (50 km) of eastward displacement that was active during the Cretaceous-Eocene Sevier orogeny (Yonkee and others, 2019). In the quadrangle, the Willard thrust places Neoproterozoic through Ordovician strata in the hanging wall over a fault-bounded lozenge of Cambrian strata and footwall Jurassic and Triassic strata (see cross section on Plate 2). Neoproterozoic strata comprise a succession of mostly clastic rocks deposited during rifting of western North America and breakup of the supercontinent Rodinia (Yonkee and others, 2014). These rocks include the Cryogenian-age Perry Canyon and Maple Canyon Formations, and the Ediacaran-age Kelley Canyon Formation, Papoose Creek Formation, Caddy Canyon Quartzite, Inkom Formation, Mutual Formation, and Browns Hole Formation. The Browns Hole Formation is a sequence of interbedded volcaniclastic rock and basalt lava flows that provides the only radiometric age control in the quadrangle. Provow and others (2021) reported a ~610 Ma detrital apatite U-Pb age from volcaniclastic sandstone at the base of the formation, Crittenden and Wallace (1973) reported a 580 ± 14 Ma K-Ar hornblende age for a volcanic clast, and Verdel (2009) reported a 609 ± 25 Ma U-Pb apatite age for a basalt flow near the top of the formation. Cambrian strata in the hanging wall include a thick basal clastic sequence (Geertsen Canyon Quartzite) overlain by a thick sequence of interbedded limestone, shale, and dolomite (Langston, Ute, and Blacksmith Formations). Hanging wall rocks are deformed by Willard thrust-related structures, including the Browns Hole anticline, Maple Canyon thrust, and numerous smaller folds and minor faults. Footwall rocks of the Willard thrust include highly deformed Cambrian strata within a fault-bounded lozenge exposed in the southern part of the quadrangle, and Jurassic and Triassic rocks exposed just south of the quadrangle. The Paleocene-Eocene Wasatch Formation unconformably overlies older rocks and was deposited over considerable paleotopography developed during late stages of the Sevier orogeny. The southwest part of the quadrangle is cut by a southwest-dipping normal fault system that bounds the east side of Ogden Valley. This fault is interpreted to have experienced an early phase of slip during local late Eocene to Oligocene collapse of the Sevier belt and deposition of volcanic and volcaniclastic rocks (Norwood Tuff) exposed west of the quadrangle (Sorensen and Crittenden, 1979), and a younger phase of slip during Neogene Basin and Range extension (Zoback, 1983). Lacustrine deposits and shorelines of Pleistocene-age Lake Bonneville are present in the southwest corner of the quadrangle near the mouth of the South Fork of the Ogden River and record the highstand of Lake Bonneville (Oviatt, 2015). Pleistocene glacial deposits, present in the northwest corner of the map, are likely related to the Pinedale glaciation, commonly expressed by two moraine building episodes in the Wasatch Range (Quirk and others, 2020). Numerous incised alluvial deposits and geomorphic surfaces are present along major drainages and record pre- and post-Lake Bonneville aggradational and degradational alluvial and colluvial sequences. Mass-movement deposits, including historically active landslides, are present throughout the quadrangle. Crittenden (1972) mapped the Browns Hole quadrangle at 1:24,000 scale, which provided an excellent foundation for the general stratigraphy and structure, but the 1972 map lacked important details of unconsolidated surficial units. As part of 1:62,500 scale mapping of the Ogden 30'x60' quadrangle, Coogan and King (2016) updated stratigraphic nomenclature, revised some contacts, and added more details for surficial units. For this map, we utilized new techniques for data acquisition and analysis to delineate surficial deposits, bedrock contacts, and faults more accurately and precisely. Mapping and field data collection were largely done in 2021–2022 using a combination of GPS-enabled tablets equipped with georectified aerial imagery (U.S. Department of Agriculture [USDA] National Agriculture Imagery Program [NAIP], 2009), orthoimagery (Utah Geospatial Resource Center [UGRC] State Geographic Information Database, 2018b, 2018c; 2021a, 2021b), and lidar data (UGRC State Geographic Information Database, 2006; 2011; 2013–2014; 2018a), previously published geologic maps, topographic maps, and applications for digital attitude collection. We also used hand-held GPS units, Brunton compasses, and field notebooks to collect geologic data. Field data were transferred to a Geographic Information System (GIS), where the map was compiled and completed.

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