Depositional Environments, Lithostratigraphy, and Biostratigraphy of the White River and Arikaree Groups (Late Eocene to Early Miocene, North America)

1998 ◽  
Author(s):  
Dennis O. Terry ◽  
Hannan E. LaGarry ◽  
Robert M. Hunt
Keyword(s):  
North America ◽  
Late Eocene ◽  
Depositional Environments ◽  
Early Miocene ◽  
White River

Age and Depositional Environments of Tertiary Rocks of Nootka Island, British Columbia (92-E): Mollusks Versus Foraminifers

1973 ◽  
Vol 10 (3) ◽  
pp. 331-365 ◽  
Author(s):  
J. A. Jeletzky
Keyword(s):  
Vancouver Island ◽  
Late Eocene ◽  
Middle Part ◽  
Depositional Environments ◽  
Early Miocene ◽  
Western Coast ◽  
Lower Miocene ◽  
Stratigraphic Position ◽  
The Rich ◽  
Latest Eocene

Conflicting interpretations of age and depositional environment of the Tertiary rocks of Nootka Island and adjacent areas of Vancouver Island resulting from studies of their molluskan and foraminiferal faunas appear to be caused by:1. A conflict of opinion concerning the correlation of regional molluskan, foraminiferal, and mammalian stages now applied to the Tertiary rocks of Western North America with units of the international biochronological standard based on the European faunas and type sections.2. Underestimation of the regional (i.e. within individual regions of the Western North American Tertiary province) biochronological value of Tertiary mollusks and other invertebrate macrofossils by many foraminiferal specialists.3. Neglect of mollusks as paleoecological indices by some foraminiferal specialists.4. Misinterpretation of paleoecological value of fossil foraminifers by some foraminiferal specialists. The application of general considerations 1 to 4 to the Tertiary rocks of Nootka Island and adjacent areas of Vancouver Island indicates that:1. A micropaleontological interpretation of the whole of Divisions A and B as bathyal deposits formed at depths of about 2000 ft (610 m) is unwarranted. The molluskan fauna present in the greater part of these units indicates they are predominantly littoral to outer neritic (0 to 800 ft (0 to 244 m)) deposits. Only the middle part of Division B could have been a bathyal (i.e. more than 800 ft (244 m) deep) deposit.A turbiditic redeposition of coarse clastics of Division A into the bathyal depth is ruled out by the state of preservation of its macrofossils, lithology of rocks, and the abundance of regular rows of early diagenetic concretions which maintain their stratigraphic position over considerable distances. The shales of Division B are not redeposited turbidites for the same reasons. If the abundance of allegedly bathyal foraminifers throughout the thickness of these two units will be confirmed by proper documentation and by further research it would be necessary to interpret their association with neritic macro-invertebrates as having been caused by the influence of strong upwelling currents which lowered the temperature of inshore waters and so made them habitable for these foraminifers.2. The recently proposed late Eocene dating of the upper part of Division A and the lower and middle parts of Division B cannot be justified either by the molluskan or by the foraminiferal fauna. The previously proposed early to mid-Oligocene age of these units remains valid regardless of whether one places them into the late Refugian foraminiferal stage or in the Lincoln molluskan stage.3. Even if it is valid, the unsupported claim of the presence of Bulimina schencki fauna does not indicate the correlation of these beds with the late Narizian, as this fauna is closely allied to and is probably contemporary with the early Refugian faunas of southern California. However, these beds may be of a latest Eocene age if the presence of Bulimina schencki fauna will be confirmed.4. The upper part of Division B contains an apparently Lower Blakeley macrofauna suggestive of late Oligocene age in terms of the generally accepted molluskan chronology. The early to mid-Zemorrian (=mid-Oligocene) dating of its foraminifer fauna reflects the divergent micropaleontological tradition which favors the placement of the Oligocene/Miocene boundary at the top of the Zemorrian stage.5. The suggested late Miocene to early Pliocene age of a shallow water foraminifer fauna of Division C of Nootka Island is contradicted by its stratigraphic position underneath the reliably dated Division D (see below). Only the upper part of Division C appears to be a neritic to ?littoral deposit. Its lower part is more likely an outermost neritic to uppermost bathyal deposit.6. The rich and diagnostic upper Blakeley (=lower Miocene) molluskan fauna of Division D is indubitably correlative with that of the type Sooke Formation of Southeastern Vancouver Island and with that of the "Sooke" Formation of the Seattle area. The early Miocene age of these three units is confirmed by the presence of a primitive whale tentatively referred to the order of Archaeoceti and the desmostylan genus Cornwallius in the type Sooke Formation. These data discredit the recently proposed early to early middle Pliocene dating of foraminifers of the Division D and the type Sooke Formation.7. No post-lower Miocene rocks are known to outcrop anywhere on the western coast of Vancouver Island contrary to the recent claims of some micropaleontologists. Also, there is no evidence of an unconformity separating the lower Miocene Division D from the underlying Oligocene to ?lowest Miocene Divisions A, B, and C. All four units appear to form part of a single invasion of a shelf-like (predominantly outer neritic to uppermost bathyal) Oligocene – early Miocene sea onto the southwestern part of Nootka Island. This sea, which may have been deeper and represented by a different facies elsewhere (i.e. Hesquiat Peninsula, Pachena–Sooke area), apparently withdrew completely and permanently from the west coast of Vancouver Island in the latest early Miocene.

scholarly journals Coal petrology analysis and implications in depositional environments from upper Cretaceous to Miocene: a study case in the Eastern Cordillera of Colombia

2021 ◽  
Author(s):  
Clara Guatame ◽  
Marco Rincón
Keyword(s):  
Late Cretaceous ◽  
Foreland Basin ◽  
Late Eocene ◽  
Depositional Environments ◽  
Estuarine System ◽  
Eastern Cordillera ◽  
Stratigraphic Position ◽  
San Fernando ◽  
Coal Facies ◽  
Oil Sector

AbstractThe Piedemonte Llanero Basin is located on the eastern side of the Eastern Cordillera of the Colombian Andes. It has been the subject of numerous geological studies carried out for the oil sector, mainly. This study presents the coal-petrographical features of 15 coal seams of four geological formations from Late Cretaceous to Middle Miocene (Chipaque formation, Palmichal group, Arcillas del Limbo formation, and San Fernando formation). Analysis of 33 samples indicates enrichment in vitrinite, while liptinite and inertinite concentrations vary according to the stratigraphic position. Reflectance indicates that the coal range gradually decreases from highly volatile bituminous C (Chipaque formation) to subbituminous C (San Fernando formation). The microlithotypes with the highest concentrations are clarite and vitrinertoliptite. Maceral composition and coal facies indicate changes in the depositional conditions of the sequence. The precursor peat from Late Cretaceous to Late Paleocene accumulated under limnic conditions followed by telmatic in Late Eocene–Early Miocene. The coal facies indices show wet conditions in forest swamps with variations in the flooding surface, influxes of brackish water and good tissue preservation. The tectonic conditions along the Piedemonte Llanero basin is evident, from post-rift to foreland basin, evidenced by oxic and anoxic periods reflected in the maceral composition and its morphology. The coal environment corresponds to an estuarine system started in the Chipaque formation evolving to the lacustrine conditions in the San Fernando formation.

The diet ofLeptomeryxsp. from the Late Eocene Yolomécatl Formation, NW Oaxaca, Sierra Madre del Sur Morphotectonic Province, SE México and its palaeoecological significance

2017 ◽  
Vol 155 (1) ◽  
pp. 203-208
Author(s):  
ISMAEL FERRUSQUÍA-VILLAFRANCA ◽  
VÍCTOR ADRIÁN PÉREZ-CRESPO ◽  
JOSÉ E. RUIZ-GONZÁLEZ ◽  
ENRIQUE MARTÍNEZ-HERNÁNDEZ ◽  
PEDRO MORALES-PUENTE
Keyword(s):  
North America ◽  
Dental Enamel ◽  
Late Eocene ◽  
C3 Plants ◽  
Congeneric Species ◽  
Open Forest ◽  
Tropical Conditions ◽  
Sierra Madre ◽  
Sierra Madre Del Sur ◽  
Oxygen Isotopic

AbstractThe diet and habitat ofLeptomeryxsp. from the Late Uintan Yolomécatl Formation of NW Oaxaca, SE Mexico were inferred using dental enamel carbon and oxygen isotopic relationships, and compared with those of congeneric species from temperate North America. Results show thatLeptomeryxsp. fed on C3 plants and lived in open forest or forest/savanna ecotone. The palynoflora and co-occurrence of perissodactyls and artiodactyls that live in an environment like that ofLeptomeryxsupport this interpretation. Further, both records disclose that in NW Oaxaca (southern North America) tropical conditions prevailed at that time, unlike that of temperate North America.

scholarly journals Age and driving mechanisms of the Eocene–Oligocene transition from astronomical tuning of a lacustrine record (Rennes Basin, France)

2021 ◽  
Vol 17 (6) ◽  
pp. 2343-2360
Author(s):  
Slah Boulila ◽  
Guillaume Dupont-Nivet ◽  
Bruno Galbrun ◽  
Hugues Bauer ◽  
Jean-Jacques Châteauneuf
Keyword(s):  
Hydrological Cycle ◽  
Sedimentary Facies ◽  
Late Eocene ◽  
Depositional Environments ◽  
Orbital Eccentricity ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Climate Conditions ◽  
Driving Mechanisms ◽  
Natural Gamma

Abstract. The Eocene–Oligocene Transition (EOT) marks the onset of the Antarctic glaciation and the switch from greenhouse to icehouse climates. However, the driving mechanisms and the precise timing of the EOT remain controversial mostly due to the lack of well-dated stratigraphic records, especially in continental environments. Here we present a cyclo-magnetostratigraphic and sedimentological study of a ∼ 7.6 Myr long lacustrine record spanning the late Eocene to the earliest Oligocene, from a drill core in the Rennes Basin (France). Cyclostratigraphic analysis of natural gamma radiation (NGR) log data yields duration estimates of Chrons C12r through C16n.1n, providing additional constraints on the Eocene timescale. Correlations between the orbital eccentricity curve and the 405 kyr tuned NGR time series indicate that 33.71 and 34.10 Ma are the most likely proposed ages of the EO boundary. Additionally, the 405 kyr tuning calibrates the most pronounced NGR cyclicity to a period of ∼1 Myr, matching the g1–g5 eccentricity term, supporting its significant expression in continental depositional environments, and hypothesizing that the paleolake level may have behaved as a low-pass filter for orbital forcing. Two prominent changes in the sedimentary facies were detected across the EOT, which are temporally equivalent to the two main climatic steps, EOT-1 and Oi-1. We suggest that these two facies changes reflect the two major Antarctic cooling/glacial phases via the hydrological cycle, as significant shifts to drier and cooler climate conditions. Finally, the interval spanning the EOT precursor glacial event through EOT-1 is remarkably dominated by obliquity. This suggests preconditioning of the major Antarctic glaciation, either from obliquity directly affecting the formation/(in)stability of the incipient Antarctic Ice Sheet (AIS), or through obliquity modulation of the North Atlantic Deep Water production.

scholarly journals New data on the Dogger - Cenomanian stratigraphy of Tripolitza series in Central Crete

2018 ◽  
Vol 34 (2) ◽  
pp. 565
Author(s):  
Α. ΖΑΜΠΕΤΑΚΗ - ΛΕΚΚΑ ◽  
Α. ΑΛΕΞΟΠΟΥΛΟΣ
Keyword(s):  
Early Cretaceous ◽  
Late Eocene ◽  
Depositional Environments ◽  
Late Triassic ◽  
Late Paleozoic ◽  
Carbonate Microfacies ◽  
Aegean Islands ◽  
Lower Aptian ◽  
Sedimentation Conditions

Tripolitza series represents the eastern part of the Gavrovo - Tripolitza platform. It outcrops in central and southeastern Peloponnesus, Crete and the Aegean islands. Its stratigraphie column starts with a volcano-sedimentary, clastic sequences (the Tyros beds), of Late Paleozoic to Late Triassic age, followed by a carbonate series of Late Triassic to Late Eocene age and a tertiary flysch. On account of intense dolomitisation as well as of rarity of fossils, the stratigraphy of Tripolitza series is not so well known as the Gavrovo series. Recent investigation attempts to complete the puzzle of Tripolitza's stratigraphie column and to reconstruct the paleogeographic sedimentation conditions. In this paper, we study some stratigraphie sections, which are taken in different places in northern – central Crete(Fig.l). New data about the stratigraphy and the sedimentation conditions of the Tripolitza series during Late Dogger to Cenomanian, complete older ones and provide information about the paleogeographic evolution of the platform. Late Dogger is determinated by Pfenderina salernitana. It is overlain by a carbonate series containing Cladocoropsis mirabilis and Macroporella sellii, dating Early Malm. Early Malm (Oxfordian - Early Kimmeridgian) is characterized by the presence of Cladocoropsis mirabilis, Kurnubia palastiniensis, Neokilianina rahonensis, Parurgonina caelinensis. Late Malm (Late Kimmeridgian - Portlandian) is characterized by Clypeina jurassica and Kurnubia palastiniensis. Early Cretaceous (Valanginian - Barremian) is determinated by Salpingoporella katzeri and Orbitolinopsis capuensis. Early Aptian is determinated by Palorbitolina lenticularis, Salpingoporella dinarica, Debarina hahounerensis, Pseudocyclammina hedbergi. Late(?) Aptian comprises Sabaudia minuta, Cuneolina hensoni, Cuneolina laurentii, Glomospira urgoniana. Albian is characterized by the disappearence of Cuneolina hensoni and Cuneolina laurentii, while Praechrysalidina infracretacea and Cretacicladus minervini are present. Late Albian is determined by the presence of "Coskinolina" bronnimanni. Early Cenomanian is not determinated by characteristic microfossils. Upper Cenomanian is overlain in comformity with upper Albian - lower Cenomanian carbonates. It is characterized by Chrysalidina gradata, Pseudorhapydionina dubia, Pseudorhapydionina laurinensis, Nummoloculina heimi, Broeckina balcanica, Nezzazata gyra, Biconcava bentori, Trochospira anvimelechi. Sedimentation took place in a peritidal environment. We observe alternations of subtidal and intratidal to supratidal conditions of sedimentation. Comparison between the carbonate microfacies of different sections representing synchronous deposits on different places of the platform, show lateral differentiation of depositional environments, from subtidal to supratidal, even supported short and local emersive episodes, (compare lower Aptian deposits of Profitis Ilias and Pinakianou sections, upper Albian deposits of Kythia and Karouzanos sections in present paper, as well as upper Cenomanian deposits of Karouzanos section in this paper, Louloudaki section (ZAMBETAKIS-LEKKAS et al. 1995 and Vitina section ZAMBETAKIS et al. 1988, Varassova section BERNIER & FLEURY 1980, Gavrovo mountain I.G.R.S. & I.F.P. 1966)(Fig.2). Similar sedimentation characterize the perimediterranean platforms during this period (SARTONI & CRESCENTI 1962, DE CASTRO 1962, FARINACCI & RADOICIC 1964, GUSIC 1969, GUSIC, NIKLER & SOKAC 1971, VELIC 1977, CHIOCCHINI et. al.1979, LUPERTO SINNI & MASSE 1993).

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