Distribution and stratigraphic correlation of upper Paleocene and lower Eocene fossil mammal and plant localities of the Fort Union, Willwood, and Tatman formations, southern Bighorn Basin, Wyoming

1994 ◽  
Author(s):  
T.M. Bown ◽  
K.D. Rose ◽  
E.L. Simons ◽  
S.L. Wing
Keyword(s):  
Stratigraphic Correlation ◽  
Bighorn Basin ◽  
Lower Eocene ◽  
Upper Paleocene

scholarly journals Astronomical climate control on paleosol stacking patterns in the upper Paleocene–lower Eocene Willwood Formation, Bighorn Basin, Wyoming

Geology ◽  
2008 ◽  
Vol 36 (7) ◽  
pp. 531 ◽  
Author(s):  
Hayfaa Abdul Aziz ◽  
Frits J. Hilgen ◽  
Gerson M. van Luijk ◽  
Appy Sluijs ◽  
Mary J. Kraus ◽  
...  
Keyword(s):  
Bighorn Basin ◽  
Climate Control ◽  
Lower Eocene ◽  
Willwood Formation ◽  
Stacking Patterns ◽  
Upper Paleocene

scholarly journals Speleogenesis and depositional hystory of paleokarst phreatic caves/cavities; Podgrad, SW Slovenia

2021 ◽  
Author(s):  
Bojan Otoničar
Keyword(s):  
Host Rock ◽  
Upper Cretaceous ◽  
Coarse Grained ◽  
Mixing Zone ◽  
Carbonate Sediment ◽  
Lower Eocene ◽  
The Third ◽  
Cave Sediments ◽  
Upper Paleocene ◽  
Δ13c And Δ18o

The studied palaeokarst corresponds to an uplifted peripheral foreland bulge when Upper Cretaceous diagenetically immature eugenetic carbonates were subaerially exposed, karstified and subsequently overlain by upper Paleocene/lower Eocene palustrine limestone. Among the subsurface paleokarstic features, both vadose and phreatic forms occur.  The phreatic caves/cavities include features characteristic of the mixing zone speleogenesis at the interface between freshwater (brackish water) lenses and the underlying seawater. They were found in various positions with respect to the paleokarstic surface, the deepest being about 75 m below the surface. Three indistinct horizons of cavities/caves and intermediate vugs were recognized. Subsequently, all cavities were completely filled with detrital sediments and speleothems in the phreatic and vadose zones. In general, the phreatic cavities of the lower two horizons are geopetally filled with mudstone derived from incomplete dissolution of the host rock and overlain by coarse-grained, blocky calcite. Shallower below the paleokarst surface, a large phreatic cave of the third horizon is filled with flowstone overlain by reddish micritic carbonate sediment with intercalated calcite rafts. In the upper part of the cave, sediments derived from the paleokarst surface are gradually becoming more abundant. Vadose channels, which may also intersect the cave sediments, are mainly filled with "pedogenic" material derived from the paleokarst surface. Immediately prior to marine transgression over the paleokarst surface, some cavities were filled with marine-derived microturbidites. In general, the diversity of cave fills and the amount of surface material decrease with distance from the paleokarst surface. Below the paleokarst surface, the δ13C and δ18O values of a host rock and cavity deposits show good correlation with trends significant for meteoric diagenesis. It is shown that deposits associated with phreatic caves can be of great importance for the study of the speleogenetic, geomorphological and hydrogeological evolution of certain palaeokarst regions.

Reappraisal of arctostylopid mammal Kazachostylops occidentalis from the late Paleocene of Kazakhstan and phylogenetic relationships within Arctostylopida

2019 ◽  
Vol 94 (3) ◽  
pp. 568-579
Author(s):  
Alexander O. Averianov
Keyword(s):  
Phylogenetic Analysis ◽  
North American ◽  
Phylogenetic Relationships ◽  
New Genus ◽  
Principal Component ◽  
Sister Taxon ◽  
Phylogenetic Hypothesis ◽  
Lower Eocene ◽  
Principal Component Analyses ◽  
Upper Paleocene

AbstractKazachostylops occidentalis Nesov, 1987b, based on partial maxilla and dentary from the upper Paleocene Zhylga locality in South Kazakhstan, is redescribed. A new phylogenetic hypothesis of Arctostylopida is proposed based on phylogenetic analysis of 26 characters and 17 taxa. Kazachostylops is recovered as a sister taxon to the Arctostylopinae, the advanced clade of Asian and North American arctostylopids characterized by pseudohypocone on upper molars and reduced trigonid of lower molars, with the ectolophid being attached labial on the trigonid. Kazachostylops differs from more basal arctostylopids (Asiostylops, Allostylops, Bothriostylops, and Wanostylops) by higher-crowned molars, M1–3 metaconule absent, m1–3 entoconid connected with ectolophid by entolophid, and m2 wider than m1 and m3. Principal component analyses of the upper and lower dentition of arctostylopids show great distinctness of Kazachostylops from other members of the group. The arctostylopid taxa are reviewed, and the new genus Enantiostylops is erected for ‘Sinostylops’ progressus Tang and Yan, 1976 from the lower Eocene of China, because of uniquely concave parastylar area on upper molars.UUID: http://zoobank.org/a46d8f29-fd73-4e59-88dc-fcc55b12d1d3

scholarly journals Late Paleocene event chronology; unconformities, not diachrony

2000 ◽  
Vol 171 (3) ◽  
pp. 367-378 ◽  
Author(s):  
Marie-Pierre Aubry ◽  
Benjamin S. Cramer ◽  
Kenneth G. Miller ◽  
James D. Wright ◽  
Dennis V. Kent ◽  
...  
Keyword(s):  
Planktonic Foraminifera ◽  
Calcareous Nannoplankton ◽  
Lower Eocene ◽  
Late Paleocene ◽  
Relative Chronology ◽  
Carbon Isotope Excursion ◽  
Thermal Maximum ◽  
Unequivocal Identification ◽  
Upper Paleocene ◽  
Reference Section

Abstract The chronology of the events associated with the late Paleocene thermal maximum (LPTM, Chron C24r) has been established through the construction of a composite reference section that involved chemomagnetobiostratigraphic correlations and assumed minimum diachrony of biostratigraphic events. On this basis, discrepancies between correlations in different sections were explained by inferred unconformities. However, diachrony between distant sections cannot be ruled out. We report here on two geographically close sections drilled onshore New Jersey that yield different records of chemomagnetobiostratigraphic correlations in the interval representing Chron C24r. Because of their proximity ( approximately 40 km apart), diachrony of biostratigraphic events between the two sections can be ruled out. In contrast, the marked lithologic disconformities in the sections explain well the different records of events. We thus conclude that the current relative chronology for Chron C24r is firmly based and that the upper Paleocene-lower Eocene stratigraphic record yields multiple unconformities, with Subzone NP9b rarely sampled. We examine the implications that undeciphered unconformities may have on the identification of proxies for paleoceanographic reconstruction, in particular with regard to the identification of the carbon isotope excursion (CIE) that reflects a dramatic latest Paleocene disturbance of the carbon cycle. We propose biostratigraphic means (short-lived calcareous nannoplankton and planktonic foraminifera taxa) that permit the unequivocal identification of the CIE not only in the oceanic realm but also in neritic settings.

scholarly journals U-Pb detrital zircon geochronology of the Upper Paleocene to Lower Eocene Wilcox Group, east-central Texas

Geosphere ◽  
2016 ◽  
Vol 12 (5) ◽  
pp. 1517-1531 ◽  
Author(s):  
Preston J. Wahl ◽  
Thomas E. Yancey ◽  
Michael C. Pope ◽  
Brent V. Miller ◽  
Walter B. Ayers
Keyword(s):  
Detrital Zircon ◽  
Zircon Geochronology ◽  
Lower Eocene ◽  
East Central ◽  
Detrital Zircon Geochronology ◽  
Central Texas ◽  
Upper Paleocene

Age of metamorphism in the Lesser Himalaya and the Main Central Thrust zone, Garhwal India: results of illite crystallinity,40Ar–39Ar fusion and K–Ar studies

1995 ◽  
Vol 132 (2) ◽  
pp. 139-149 ◽  
Author(s):  
G. J. H. Oliver ◽  
M. R. W. Johnson ◽  
A. E. Fallick
Keyword(s):  
Regional Metamorphism ◽  
Low Grade ◽  
Supporting Evidence ◽  
Lesser Himalaya ◽  
Main Central Thrust ◽  
Illite Crystallinity ◽  
Lower Eocene ◽  
Thrust Zone ◽  
Lower Palaeozoic ◽  
Upper Paleocene

AbstractIllite crystallinity data from the Lesser Himalaya of Garhwal show that the upper Paleocene-lower Eocene Subathu Formation, deposited immediately prior to or early in the Himalayan collision, has not suffered significant regional metamorphism. The regional metamorphism in the upper Precambrian–lower Palaeozoic Lesser Himalaya must therefore be precollisional. Illite crystallinity results from Lesser Himalayan fossiliferous Permian strata show grades of metamorphism intermediate between upper Paleocene–lower Eocene and Proterozoic–lower Palaeozoic strata indicating a pre-Permian regional metamorphism for the latter.K–Ar whole rock cooling ages provide supporting evidence for pre-collisional regional metamorphism in the Lesser Himalaya. Slates and phyllites below the Main Central Thrust (MCT) show pre-Cenozoic whole rock ages, as old as Ordovician (486 Ma). Whilst resetting of K–Ar whole rock ages has occurred locally in pervasively cleaved Palaeozoic strata (near thrusts?), fracture cleaved Permian and upper Paleocene–lower Eocene sediments give whole rock ages compatible with diagenesis. The illite crystallinity results confirm that these sediments have not been heated above mica blocking temperatures.Muscovite40Ar–39Ar and K–Ar mineral ages within the 5 km thick MCT zone are as young as 8 Ma indicating that temperatures of above ~ 350°C were maintained in the MCT zone for over 10 Ma after high temperature (~ 550°C) shearing on the MCT. This heating did not affect the MCT footwall Lesser Himalaya to any regional extent, where pre-Permian low grade regional metamorphism has not been overprinted.

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