Braided-Stream and Alluvial-Fan Depositional Environment of Lower to Middle Eocene Ione Formation, Madera County, California: ABSTRACT

In the Archean greenstone belt at Sioux Lookout, N.W. Ontario, a lowermost belt of volcanic rocks is unconformably overlain by sediments of the Abram Group. Our mapping has subdivided the Abram Group into three formations. The lowest (Ament Bay Formation) consists of interbedded conglomerates and sandstones. The sandstones contain large-scale cross-stratification, and the conglomerates and sandstones both lack graded bedding. The depositional environment was a subaerial alluvial fan—this is the first description of such a feature based upon modern sedimentological work in Archean rocks. The Daredevil Formation conformably overlies the Ament Bay Formation, and is composed of felsic and basic tuffs, and some interbedded turbidites. The uppermost (Little Vermilion) Formation is composed entirely of turbidites.The petrography of the sand, and large clasts, in the Ament Bay Formation indicates derivation from a dominantly granodioritic terrain. Some granodiorite boulders contain greenstone xenoliths, implying intrusion of the granodiorite after formation of the lowermost belt of volcanic rocks.In a final section of the paper, we define two Archean facies associations—a Resedimented association containing turbidites, pebbly mudstones, resedimented conglomerates, and basinal black argillites; and a Continental association, containing alluvial fan deposits, and possible coastal deposits from South Africa and Australia. The facies sequence in the Sioux Lookout belt is Continental followed by Resedimented facies, the reverse of the normal geosynclinal flysch (resedimented) → molasse (continental) sequence.

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The Paleogene Tectonostratigraphy Of Northern Part Masalima Trench Basin

Journal of Geoscience Engineering Environment and Technology ◽

10.24273/jgeet.2016.11.2 ◽

2016 ◽

Vol 1 (1) ◽

pp. 7

Author(s):

Luhut Pardamean Siringoringo ◽

Dardji Noeradi

Keyword(s):

Depositional Environment ◽

Middle Eocene ◽

Normal Faults ◽

Tectonic Structure ◽

Shallow Marine ◽

Early Oligocene ◽

Basin Formation ◽

Java Sea ◽

Seismic Sections ◽

Well Data

Northern part of Masalima Trench Basin is located in the southern part of the Strait of Makassar, which includes Masalima Trough and Massalima High. The area of research is an extension of the South Makassar Basin which extends from South Makassar Basin to the Northeast part of Java Sea. Subsurface data are used such as 2D seismic sections (21 lines) and data drilling wells (2 wells) to understand the tectonic structure in the basin formation and understand the stratigraphic order of basin. Based on well data can be known that Northern part Masalima Trench Basin is aborted rift because marked by post rift phase. Northern part Masalima Trench Basin was formed by normal faults which have trend northeast-southwest with pre rift, early syn rift, late syn rift, and post rift sediment geometry. Early syn rift sediment was Middle Eocene, late syn rift sediment was Middle Eocene till Early Oligocene and post rift sediment was Early Oligocene till Early Miocene. The Depositional environment of early syn rift phase such as beach, shallow marine, and land. The Depositional environment of late syn rift phase such as beach till deep marine, and the depositional environment of post rift is deep marine.

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Stratigraphy, age, and paleogeography of the Eocene Chuckanut Formation, northwest Washington

Canadian Journal of Earth Sciences ◽

10.1139/e84-010 ◽

1984 ◽

Vol 21 (1) ◽

pp. 92-106 ◽

Cited By ~ 37

Author(s):

Samuel Y. Johnson

Keyword(s):

Large Scale ◽

Middle Eocene ◽

Alluvial Fan ◽

Fluvial System ◽

Upper Eocene ◽

Meandering River ◽

The North ◽

River Deposits ◽

Metamorphic Terranes ◽

Eastern Washington

The Eocene Chuckanut Formation of Washington's North Cascades comprises as much as 6000 m of alluvial strata and is one of the thickest nonmarine sequences in North America. It is exposed in several disconnected outcrop belts that are remnants of what was probably an extensive fluvial system in western Washington. In this study, seven stratigraphic members are defined in the main outcrop belt of the Chuckanut Formation near the town of Bellingham. Their ages, based on fission-track zircon dates, palynologic studies, and correlation by mapping, extend from the Early to the Late Eocene.Three types of fluvial systems contributed to the Chuckanut Formation and are distinguished on the basis of their lithology, sedimentology, and petrology. The first comprises fine-load meandering-river deposits of the Lower Eocene Bellingham Bay Member and the Middle Eocene Slide Member. Sandstones are arkosic and had their main source in rapidly uplifted, high-grade metamorphic terranes in eastern Washington. The second type comprises braided- and coarse-load meandering-river deposits of the Middle to Upper Eocene Padden Member. The Padden Member occurs only in the western part of the outcrop belt and was derived form the Coast Plutonic Complex of southern British Columbia to the north. Sandstones are arkosic but are richer in lithic fragments than sandstones of the underlying Bellingham Bay Member and interfingering Slide Member. The third fluvial-system type comprises conglomerate-rich braided-river and alluvial-fan deposits of the lower Middle Eocene Governors Point Member and the Middle to Upper (?) Eocene Maple Falls, Warnick, and Bald Mountain members. Sandstones from these units are both lithic and arkosic. These strata were locally derived from uplifts on the northern basin margin.The petrology of down-basin correlatives of the Chuckanut Formation on the northeast Olympic Peninsula is incompatible with derivation through the Chuckanut fluvial system. This petrologic contrast supports a model for large-scale Eocene dextral offsets in the continental margin of Washington.

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Sedimentary Cyclicity in the Upper Paleocene- Eocene Successions of the Haymana Basin (Ankara, Turkey): Responses of Fossils to Cyclicity

10.5194/egusphere-egu2020-8 ◽

2020 ◽

Author(s):

Nilya Bengül

Keyword(s):

Depositional Environment ◽

Middle Eocene ◽

Planktonic Foraminifera ◽

High Energy ◽

Central Anatolia ◽

Accretionary Wedge ◽

Depositional Model ◽

Stratigraphic Sequence ◽

Large Benthic Foraminifera ◽

Upper Paleocene

The Haymana Basin in central Anatolia (Turkey) formed during the closure of the Neo-Tethys on Late Cretaceous to Middle Eocene as a forearc accretionary wedge. Late Paleocene to Middle Eocene aged units in this basin are exposed near &#199;ayraz Village, Haymana. The &#199;ayraz Formation is the youngest unit of the Haymana Basin, and it is represented by packages of nummulitic banks, and the intercalation of calcareous mudstones. The aim of this study is to investigate the sedimentary cyclicity and depositional sequences in the Upper Paleocene- Eocene successions of the Haymana Basin. To be able to achieve this objective, a stratigraphic section has been measured through this succession. In this study, detailed microfacies analyses of the shallow-water carbonate successions indicate a ramp type depositional model of the carbonate rocks. The facies composed of Alveolina sp., Orbitolites sp., and&#160; Miliolids that indicate low energy depositional environment . After that depositional environment to&#160; the shoal; the facies composed of Nummulites spp., Assilina spp. occur and increase their abundance towards high-energy environments. Absence of the Alveolina sp., Orbitolites sp., and Miliolids. occur in accordance with that. The facies composed of Nummulites spp., Assilina spp. become associated with Discocyclina sp. towards to open sea on the ramp, and the shallow open marine part is represented by the shale with the association of planktonic foraminifera. Lateral relationships of the facies from proximal (inner ramp) to the distal (mid ramp) part of the ramp are investigated by using the knowledge of paleoecology preferences of the fossils, lithologic data of the rocks and biological aspects of the fossils.&#160; The fossil associations and their indicator environments can be used in vertical changes of the facies as in the lateral relationships of the facies. It has potential to derive cyclic relationships of the stratigraphic sequence. Therefore, based on the detailed microfacies analysis and change in the distribution of the fossil associations in the stacking pattern of the sequence, a composite depositional model has been suggested. At this part of the research newly acquired question is that the driven factor of these cyclic relationships of the sequence, whether it occurred by the control of the eustatic sea- level or the interplay between tectonics and the eustacy as the dominating factor in the sequence formation.&#160;Keywords: Large Benthic Foraminifera, Nummulites spp., Assilina spp., Haymana Basin, &#199;ayraz Formation

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Chaoborus Lichtenstein (Diptera: Chaoboridae) pupae from the middle Eocene of Mississippi

Journal of Paleontology ◽

10.1017/s0022336000024252 ◽

1998 ◽

Vol 72 (3) ◽

pp. 491-493 ◽

Cited By ~ 1

Author(s):

John E. Johnston ◽

Art Borkent

Keyword(s):

North America ◽

Depositional Environment ◽

Middle Eocene ◽

First Record ◽

Extant Genus ◽

Clay Deposits ◽

Benton County

Pupae of the nonbiting midge Chaoborus are reported from the middle Eocene (Claibornian) Tallahatta Formation in Benton County, Mississippi. These pupae are placed within the genus Chaoborus because the shape of the respiratory organs, length of the abdomen, and shape of the anal paddles closely resemble other species of this extant genus. This occurrence represents the oldest record of Chaoborus pupae and the first record of fossil Chaoborus from North America. The flora and fauna found associated with the fossil pupae along with the known habitats of extant Chaoborus pupae indicate a lentic environment. This interpretation corresponds to the depositional environment of similar Eocene-aged clay deposits in western Tennessee.

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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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Microfacies and Palaeoenvironment of Avanah Formation (Middle Eocene) Geli Bessri in Dohuk City / North of Iraq

Tikrit Journal of Pure Science ◽

10.25130/j.v25i1.940 ◽

2020 ◽

Vol 25 (1) ◽

pp. 85

Author(s):

Mustafa A. Abdullah ◽

Faris N. Hassan ◽

Abdulsalam. M.Saleh

Keyword(s):

Benthic Foraminifera ◽

Depositional Environment ◽

Facies Analysis ◽

Middle Eocene ◽

Depositional Environments ◽

Thin Layers ◽

Marine Platform ◽

Marly Limestone

This research is based on (23) Samples selected from the Avanah Formation (Middle Eocene) in the Geli Bessri section in Dohuk to recognize the microfacies and depositional environments. The Avanah Formation consists of rocks of marly limestone and limestone containing Alveolina and thin layers of sandstone lithofacies found in the lower part of the Formation. The depositional environment was determined depending on skeletal and non- skeletal grains. The facies of the Avanah Formation were divided into four main microfacies and four submicrofacies based on skeletal and non- skeletal grains: The mudstone and wackestone, which is divided into benthic foraminifera wackestone and Rotaliids wackestone, the Formation also contains the packstone which is divided into the Rotaliid - Miliolid Lime packstone submicrofacies and benthic foraminifera lim packstone submicrofacies, in addition to the lime grainstone and also contains the Sandstone lithofacies located at the bottom of the Formation. The Avanah Formation in the middle and upper part is subjected to diagenesis process early dolomization and it is observed this through floating dolomite rohmb. According to the results of the facies analysis and the presence of foraminifera fossils, the Formation was deposited in open marine platform to restricted platform interior. http://dx.doi.org/10.25130/tjps.25.2020.014

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