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Benthic Foraminifera and geochemistry across the Paleocene-Eocene Thermal Maximum interval in Jordan

Victor M. Giraldo-Gomez, Joerg Mutterlose, Olaf G. Podlaha, Robert P. Speijer and Peter Stassen
Benthic Foraminifera and geochemistry across the Paleocene-Eocene Thermal Maximum interval in Jordan
Journal of Foraminiferal Research (April 2018) 48 (2): 100-120

Abstract

This study presents benthic foraminiferal data from two sedimentary successions across the Paleocene-Eocene Thermal Maximum (PETM) from Jordan. Calcareous nannofossil biozones NP9a, NP9b, and NP10 of latest Paleocene and earliest Eocene age were encountered in proximal (core OS-01) and distal (core OS-28) sites. Lithologically, the investigated sequence consists of marls, shales, and limestones attributed to the Muwaqqar Chalk-Marl Formation and the Um Rijam Chert Limestone Formation. The delta (super 13) C (sub org) curve records the typical carbon isotope excursion (CIE) and shows four distinctive intervals (pre-CIE, CIE-"core", CIE-"recovery", post-CIE) over the entire PETM interval in both cores. In the pre-CIE interval, the more proximal site (OS-01) shows high abundances of Neoeponides duwi co-occurring with an outer neritic Midway-type fauna. The fauna indicates meso- to eutrophic conditions in a middle- to outer-neritic setting. The more distal site (OS-28) is characterized by outer-neritic to upper-bathyal taxa (e.g., Cibicides pseudoacutus, Gavelinella beccariiformis, Nuttallides truempyi) suggesting well-ventilated, oligo- to mesotrophic seafloor conditions. The earliest Eocene corresponds to the CIE-"core" interval and is marked by a negative delta (super 13) C (sub org) signal, high TOC, low CaCO (sub 3) contents, and near absence of benthic foraminifera. Oxygen deficiency in bottom waters with increased organic flux is the most likely scenario to explain the elevated organic content at the seafloor. The subsequent CIE-"recovery" interval of early Eocene age is marked by a restoration of oxygenated seafloor conditions. The proximal site is characterized by a relatively elevated TOC content and high abundance of Lenticulina spp., Valvulineria scrobiculata and common Anomalinoides zitteli, suggesting moderate oxygen conditions and mesotrophic bottom waters. The distal site is characterized by low TOC content and the presence of Lenticulina spp., Valvulineria scrobiculata, Anomalinoides zitteli and Oridorsalis plummerae, indicating a normalization of the organic flux and moderate oxygen concentrations near the seafloor. The post-CIE interval is marked by low TOC content in both cores. Benthic foraminifera include abundant Anomalinoides zitteli and common Lenticulina spp., Valvulineria scrobiculata, Oridorsalis plummerae, Cibicidoides rigidus, Cibicidoides pharaonis, and Anomalinoides praeacutus in the proximal setting. Mesotrophic conditions and a better ventilation of bottom waters are suggested for this interval. Lenticulina spp., Valvulineria scrobiculata, and Oridorsalis plummerae are also associated with the post-CIE interval in the distal site, suggesting similar mesotrophic conditions with renewed oxygenation in bottom waters.


ISSN: 0096-1191
EISSN: 1943-264X
Coden: JFARAH
Serial Title: Journal of Foraminiferal Research
Serial Volume: 48
Serial Issue: 2
Title: Benthic Foraminifera and geochemistry across the Paleocene-Eocene Thermal Maximum interval in Jordan
Affiliation: Ruhr University Bochum, Institute for Geology, Mineralogy and Geophysics, Bochum, Germany
Pages: 100-120
Published: 201804
Text Language: English
Publisher: Cushman Foundation for Foraminiferal Research, Ithaca, NY, United States
References: 117
Accession Number: 2018-059534
Categories: StratigraphyIsotope geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Includes 2 appendices
Illustration Description: illus. incl. strat. cols., 2 plates, sketch map
N30°30'00" - N31°45'00", E36°15'00" - E37°00'00"
Secondary Affiliation: Shell Global Solutions International, NLD, NetherlandsKatholieke Universiteit Leuven, BEL, Belgium
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Abstract, Copyright, Cushman Foundation for Foraminiferal Research. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2018
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