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GEOREF RECORD

Calcareous nannofossil biostratigraphy of Eocene oil shales from central Jordan

Mohammad Alqudah, Mohammad Ali Hussein, Olaf G. Podlaha, Sander van den Boorn, Sadat Kolonic and Joerg Mutterlose
Calcareous nannofossil biostratigraphy of Eocene oil shales from central Jordan
GeoArabia (Manama) (2014) 19 (1): 117-140

Abstract

Cretaceous and Paleogene marls, rich in total organic carbon, are widespread throughout Jordan and adjoining areas. Based on planktonic foraminifera these oil shales have been assigned a late Campanian-Paleocene age in previous studies. For the current analysis a total of 283 smear slides from five wells in central Jordan have been investigated for calcareous nannofossil biostratigraphy. Findings suggest a much more differentiated age model of the oil shales than previously proposed. The oil shales studied contain abundant calcareous nannofossil taxa of Eocene age along with varying abundances of Maastrichtian and Paleocene taxa. The encountered marker species Rhomboaster cuspis, Tribrachiatus bramlettei, Tribrachiatus orthostylus, Discoaster lodoensis, Coccolithus crassus, Discoaster sublodoensis, Nannotetrina quadrata, Reticulofenestra umbilicus and Chiasmolithus solitus, indicate an Early to Middle Eocene age, while the presence of Maastrichtian and Paleocene forms suggests major reworking. The presence of Cretaceous taxa reflects either subaerial erosive input from the hinterland or submarine reworking of Cretaceous strata within the basin. The highly variable amount of reworked material and associated deposition rates in the basin may represent changes in the tectonic setting during the Eocene. We propose that the high abundances of Cretaceous and Paleocene taxa reflect an increase in accommodation space by active graben flank movements. A dominance of Eocene taxa, on the other hand, indicates either periods of little accommodation space due to graben infill or inversion-type movements of the graben itself. In any case, the youngest Eocene and autochthonous taxa represent shallower or low topography graben phases.


ISSN: 1025-6059
Serial Title: GeoArabia (Manama)
Serial Volume: 19
Serial Issue: 1
Title: Calcareous nannofossil biostratigraphy of Eocene oil shales from central Jordan
Affiliation: Ruhr University Bochum, Bochum, Germany
Pages: 117-140
Published: 2014
Text Language: English
Publisher: Gulf Petrolink in Bahrain, Manama, Bahrain
References: 55
Accession Number: 2014-073641
Categories: Economic geology, geology of energy sourcesStratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Includes appendix
Illustration Description: illus. incl. strat. cols., 2 plates, geol. sketch map
N31°19'60" - N32°10'00", E36°19'60" - E37°10'00"
Secondary Affiliation: Shell International, NLD, Netherlands
Country of Publication: Bahrain
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 201439
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