Sedimentology, sequential analysis and paleoclimate associations of the upper Paleocene-lower Eocene Chouabine Formation at the Oued Thelja section, Gafsa Basin, Southern Tunisia

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.

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GEOCHRONOLOGY, BIOSTRATIGRAPHY AND SEQUENCE STRATIGRAPHY OF A MARGINAL MARINE TO MARINE SHELF STRATIGRAPHIC SUCCESSION: UPPER PALEOCENE AND LOWER EOCENE, WILCOX GROUP, EASTERN GULF COASTAL PLAIN, U.S.A.

Geochronology, Time Scales, and Global Stratigraphic Correlation ◽

10.2110/pec.95.04.0281 ◽

1995 ◽

pp. 281-293 ◽

Cited By ~ 13

Author(s):

ERNEST A. MANCINI ◽

BERRY H. TEW

Keyword(s):

Sequence Stratigraphy ◽

Coastal Plain ◽

Gulf Coastal Plain ◽

Lower Eocene ◽

Stratigraphic Succession ◽

Upper Paleocene

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

Journal of Paleontology ◽

10.1017/jpa.2019.93 ◽

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

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

Geology ◽

10.1130/g24734a.1 ◽

2008 ◽

Vol 36 (7) ◽

pp. 531 ◽

Cited By ~ 69

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

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Late Paleocene event chronology; unconformities, not diachrony

BSGF - Earth Sciences Bulletin ◽

10.2113/171.3.367 ◽

2000 ◽

Vol 171 (3) ◽

pp. 367-378 ◽

Cited By ~ 24

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.

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