Late Eocene (Priabonian) chronostratigraphy, depositional environment, and paleosol-trace fossil associations, Pipestone Springs, southwest Montana

AbstractWalat Formation is equivalent to Bayah Formation. This formation is the beginning of Bogor basin deposition. In this case, age and environment of this formation have been analyzed by previous researchers, but the results of age and environment interpretations have different ranges, especially from its palynological aspect which until now Walat Formation is rarely analyzed using this aspect. This research was conducted to identify the age and depositional environment of Walat Formation in Sukabumi region by using pollen and spores to confirm different interpretations of previous studies. Measure section was carried out in sampling and chemical treatment method was carried out to see palynomorph content in the rock. Furthermore, data analysis was carried out with range of interval zones and pollen grouping based on their environment.The results show that Walat Formation has Late Eocene age based on the interval zone between first occurrence of Verrucatosporites usmensis and Meyeripollis naharkotensis, and the last occurence of Proxapertites operculatus, Proxapertites cursus, and Cicatricosisporites eocenicus. Walat Formation has fluvial depositional environment characterized by the dominance of Proxapertites operculatus and Proxapertites cursus. The results of this study confirm that the Walat Formation has an Eocene age and a fluvial depositional environment from a palinological aspect.

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Elemental and isotopic geochemistry of carbonate rocks from the Pila Spi Formation (Middle–Late Eocene), Kurdistan Region, Northern Iraq: implication for depositional environment

Arabian Journal of Geosciences ◽

10.1007/s12517-020-05884-9 ◽

2020 ◽

Vol 13 (18) ◽

Author(s):

Faraj Habeeb Tobia ◽

Hikmat Safi Al-Jaleel ◽

Awaz Kareem Rasul

Keyword(s):

Carbonate Rocks ◽

Depositional Environment ◽

Late Eocene ◽

Kurdistan Region ◽

Northern Iraq ◽

Isotopic Geochemistry

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Devonian depositional environments in the Darwin Mountains: Marine or non-marine?

Antarctic Science ◽

10.1017/s0954102093000276 ◽

1993 ◽

Vol 5 (2) ◽

pp. 211-220 ◽

Cited By ~ 12

Author(s):

Ken J. Woolfe

Keyword(s):

Fresh Water ◽

Depositional Environment ◽

Trace Fossils ◽

Depositional Environments ◽

Trace Fossil ◽

Glacier Area ◽

Red Beds ◽

Fossil Assemblage ◽

Considerable Debate

The depositional environment of the Devonian Taylor Group has been subject to considerable debate for over 30 years. The debate stems largely from a belief that the abundant and diverse trace fossils represent a marine ichnofauna, whereas sedimentary features, including palaeosols, desiccation polygons and red beds, are more typical of a non-marine setting. The debate is reconciled by a reinterpretation of the trace fossil assemblage which shows that the trace fossils comprise a typical fresh water (Scoyenia ichnofacies) assemblage, and their occurrence in the Taylor Group in the Darwin Glacier area is entirely consistent with deposition in a mixed fluvial-lacustrine-subaerial environment.

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The power of the physical fabric of mudstone in creating trace fossil like redoximorphic features, case study from the late Eocene, Sirt Basin

Journal of African Earth Sciences ◽

10.1016/j.jafrearsci.2020.103931 ◽

2020 ◽

Vol 170 ◽

pp. 103931

Author(s):

Abouessa Ashour ◽

Duringer Philippe ◽

Pelletier Jonathan

Keyword(s):

Late Eocene ◽

Trace Fossil ◽

Redoximorphic Features ◽

Sirt Basin

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Age and depositional environment of the Rock River coal basin, Yukon Territory, Canada

Canadian Journal of Earth Sciences ◽

10.1139/e94-079 ◽

1994 ◽

Vol 31 (5) ◽

pp. 865-880 ◽

Cited By ~ 7

Author(s):

D. G. F. Long ◽

A. R. Sweet

Keyword(s):

Depositional Environment ◽

Middle Eocene ◽

Late Eocene ◽

Yukon Territory ◽

Temperate Climate ◽

Fluvial System ◽

Coal Basin ◽

Early Oligocene ◽

Palynological Assemblage ◽

Latest Eocene

Poorly exposed Late Eocene strata in the Rock River basin, 115 km northeast of Watson Lake, accumulated in an intermontane valley with a geometry and history controlled by subsidence associated with the Rock River Fault. The sequence, as seen in one outcrop and five borehole sections, is dominated by drab mudrocks with minor sandstones and some thick lenses of coal. The mudrocks accumulated in floodplain marsh and pond settings associated with a low-gradient, possibly anastomosed, fluvial system. River banks were stable owing to the abundance of plant roots in the channel walls. Although channel sandstone and conglomerate were not identified in the core, the abundance of coarsening- and fining-upwards sets of sandstone of splay origin indicates pronounced levee development. Woody coals accumulated in areas well away from the main channel, in a series of elongate forested swamps, which were periodically inundated by flood water.The overall palynological assemblage is typical of the Eocene and Early Oligocene. A Late Eocene age is inferred from the presence of Gothanipollis in combination with the absence of index species for the Early–Middle Eocene and the latest? Eocene and Oligocene. The low miospore diversity indicates a temperate climate. The dominance of the palynological assemblage by Taxodiaceae–Cupressaceae pollen indicates wet–humid conditions.

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Lithofacies, Palynostratigraphy and Paleoecology of the Outcropping Rock Succession at Ogbunike Old Toll Gate, Niger Delta Basin, Nigeria

Journal of Geography Environment and Earth Science International ◽

10.9734/jgeesi/2020/v24i330212 ◽

2020 ◽

pp. 80-99

Author(s):

E. N. Onuigbo ◽

A. U. Okoro ◽

C. M. Okolo ◽

H. C. Okeke

Keyword(s):

Niger Delta ◽

Depositional Environment ◽

Middle Eocene ◽

Age Determination ◽

Trace Fossil ◽

High Abundance ◽

Environmental Setting ◽

Sedimentary Succession ◽

Niger Delta Basin

Aim: Sedimentary succession exposed at Ogbunike old toll gate is part of the outcropping sediments of the Niger Delta Basin and its age is controversial. The outcrop was studied for the purpose of age determination, lithostratigraphic placement and interpretation of paleoecology, paleoclimatology and depositional environment. Methodology: Lithofacies and biofacies analyses were integrated in the study. Results: Thirteen lithofacies identified include; bioturbated sandstone, ripple laminated sandstone, ripple laminated claystone, dark shale, ferruginized sandstone, carbonaceous sandstone, greyish shale, very fine sandstone, mudstone, massive claystone, coarse sandstone, cross bedded sandstone and flaser bedded sandstone lithofacies. Four lithofacies associations consisting of lower shoreface to inner neritic, fluvial channel, lagoonal/mixed flat and subtidal sandwave associations were delineated. Middle Eocene age is assigned to the succession based on the high abundance of marker pollen such as Margocolporites foveolatus, Ctenelophonidites costatus, Monocolpites marginatus, Retibrevitricolporites triangulatus, Proxapertites cursus, Bombacacidites sp. and common occurrences of Scrabratisporites simpliformis, Anacolosidites luteoides, Psilatricolporites crassus, Gabonisporis viaourouxii, Striatricolporites catatumbus and Retistephanocolporites williamsi. These co-occur with Cordosphaeridium cantharellus. Palynofloral group recovered are dominated by mangrove and palm pollen. Pteridophyte spores are also abundant whereas the hinterland pollen group is very low. Benthic foraminiferal assemblages of Textularia, Miliammina,Ammobaculites Haplophragmoides, Fursenkoina, Heterolepa, Reophax, Nodosaria, Florilus, Uvigerina, Cibicides and Bolivina recovered from the dark shale suggest deposition in an inner neritic setting. Trace fossil suite of Skolithos- Cruziana ichnofacies is an attribute of the sedimentary units. Conclusion: The sedimentary succession is part of the Ameki Group (Nanka Formation) deposited under varied environmental setting. Paleoclimate is tropical.

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Tectonics and Depositional History of the Continental Margin Off Vancouver Island, British Columbia

Canadian Journal of Earth Sciences ◽

10.1139/e72-023 ◽

1972 ◽

Vol 9 (3) ◽

pp. 280-296 ◽

Cited By ~ 29

Author(s):

D. L. Tiffin ◽

B. E. B. Cameron ◽

J. W. Murray

Keyword(s):

Continental Margin ◽

Deep Water ◽

Depositional Environment ◽

Marked Change ◽

Vancouver Island ◽

Late Eocene ◽

Transform Faults ◽

Depositional History ◽

Seismic Profiling ◽

History Of

Sampling and seismic profiling in the Tofino Basin west of Vancouver Island show there is a thick sequence of Tertiary rocks ranging in age from late Eocene to Pliocene. The rocks are mainly mudstones containing abundant foraminifera indicating a bathyal depositional environment throughout most of the Tertiary. Subsequent uplift has exposed the deep water sediments on the shelf over much of the area. Eocene-Oligocene sediments occur in a belt along the inner shelf, while Miocene and Pliocene rocks lie seaward of this. Pliocene rocks form a regressive sequence overlapping the older Tertiary, with the greatest thickness in the south.At least two major periods of deformation resulted in faulting, folding, and diapirism on the continental shelf. Deformational patterns show a marked change from north to south. North of Brooks Peninsula sediments are undeformed by folding but are truncated by faulting along the steep continental slope. The Kyuquot Uplift south of Brooks Peninsula exposes Eocene-Oligocene sediments across the shelf. Farther south Mio-Pliocene sediments unconformably overlie the uplift. Folding increases southward culminating in an area of diapirism off Nootka Sound. Elongate diapirs trend parallel or subparallel to the coastline.Tectonic features on the shelf and slope appear to be related to present and earlier configurations of nearby offshore spreading centers, plates, and transform faults. Crustal plate movements may have been responsible for the observed shelf and slope deformations.

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