scholarly journals Calcareous nannofossil biostratigraphy of Eocene oil shales from central Jordan

GeoArabia ◽  
2014 ◽  
Vol 19 (1) ◽  
pp. 117-140 ◽  
Author(s):  
Mohammad Alqudah ◽  
Mohammad Ali Hussein ◽  
Olaf G. Podlaha ◽  
Sander van den Boorn ◽  
Sadat Kolonic ◽  
...  
Keyword(s):  
Middle Eocene ◽  
Tectonic Setting ◽  
Planktonic Foraminifera ◽  
Calcareous Nannofossil ◽  
Current Analysis ◽  
Accommodation Space ◽  
Central Jordan ◽  
Age Model ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Oil Shales

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.

scholarly journals New microplanktonic biostratigraphy and depositional sequences across the Middle–Late Eocene and Oligocene boundaries in eastern Jordan

GeoArabia ◽  
2015 ◽  
Vol 20 (3) ◽  
pp. 145-172
Author(s):  
Sherif Farouk ◽  
Mahmoud Faris ◽  
Fayez Ahmad ◽  
John H. Powell
Keyword(s):  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Eastern Desert ◽  
Late Eocene ◽  
Arabian Plate ◽  
Rapid Decline ◽  
Calcareous Nannofossil ◽  
Upper Eocene ◽  
Depositional Sequences ◽  
Global Correlation

ABSTRACT The first detailed calcareous nannofossil and planktonic foraminiferal biostratigraphic and integrated lithofacies analyses of the Eocene–Oligocene transition at the Qa’ Faydat ad Dahikiya area in the Eastern Desert of Jordan, on the border with Saudi Arabia, is presented. Three calcareous nannofossil zones namely: Discoaster saipanensis (NP17), Chiasmolithus oamaruensis (NP18) and Ericsonia subdisticha (NP21), and three planktonic foraminiferal zones: upper part of Truncorotaloides rohri (E13), Globigerinatheka semiinvoluta (E14) and Cassigerinella chipolensis/Pseudohastigerina micra (O1) are identified. Calcareous nannofossil bioevents recorded in the present study show numerous discrepancies with the Standard biostratigraphic zonal schemes to detect the Middle/Upper Eocene boundary (e.g. the highest occurrences (HOs) of Chiasmolithus solitus, C. grandis, and lowest occurrences (LOs) of C. oamaruensis, Isthmolithus recurvus are not considered reliable markers for global correlation). The Middle/Upper Eocene boundary occurs in the current study above the extinctions of large muricate planktonic foraminifera (large Acarinina and Truncorotaloides spp.) which coincide within the equivalent calcareous nannofossil NP18 Zone. These microplanktonic bioevents seem to constitute more reliable markers for the base of the Upper Eocene in different provinces. The uppermost portion of the Middle Eocene is characterized by an observed drop in faunal content and, most likely, primarily denotes the effect of the major fall in eustatic sea level. A major unconformity (disconformity) marked by a mineralized hardground representing a lowstand is recorded in the present study at the Eocene–Oligocene transition that reveals an unexpected ca. 2.1 Myr duration, separating Eocene (NP18/E14 zones) from Oligocene (NP21/O1 zones). Furthermore, the microfossil turnover associated with a rapid decline of the microfossil assemblages shows a distinct drop in diversity and abundance towards the Eocene/Oligocene unconformity and is associated with a sharp lithological break marked, at the base, by a mineralized hardground representing a major sequence boundary. These bioevents, depositional sequences and the depositional hiatus correlate well with different parts of the Arabian and African plates, but the magnitude of the faunal break differs from place to place as a result of intraplate deformation during the regional Oligocene regression of Neo-Tethys on the northern Arabian Plate. The presence of the Lower Oligocene shallow-marine calcareous planktonic assemblages in the study area indicate that communication between the eastern and western provinces of the western Neo-Tethys region still existed at this time.

Oxygen isotope stratigraphy and calcareous nannofossil biostratigraphy of the Lower Pleistocene in the Boso Peninsula, central Japan

Stratigraphy ◽  
2021 ◽  
Vol 18 (2) ◽  
Author(s):  
Daisuke Kuwano ◽  
Yoshimi Kubota ◽  
Kanako Mantoku ◽  
Koji Kameo
Keyword(s):  
Oxygen Isotope ◽  
Northwestern Pacific ◽  
Calcareous Nannofossil ◽  
Boso Peninsula ◽  
Oxygen Isotope Stratigraphy ◽  
Age Model ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Isotope Stratigraphy ◽  
Pacific Coast Of Japan ◽  
Cyclic Changes

ABSTRACT: Oxygen isotope stratigraphy and calcareous nannofossil biostratigraphy in the upper part of the Kiwada Formation, which is part of the Kazusa Group in the Boso Peninsula in the central part of the Pacific coast of Japan, were examined to establish a high-resolution age model and estimate the age of the lower part of Pleistocene nannofossil biohorizons in the northwestern Pacific region. The new age model indicates that the upper part of the Kiwada Formation corresponds to Marine Isotope Stage (MIS) 41 through MIS 36. Two nannofossil biohorizons, the last occurrences of large forms of Gephyrocapsa (>5.5 micrometers) and Helicosphaera sellii,were recorded in the examined section. The LO of large Gephyrocapsa spp. coincides with the MIS 37/38 boundary which is 1241.2 plus or minus 0.4 ka. The LO of H. sellii is located in late MIS 40 and has a calculated age of 1291.4 plus or minus 1.4 ka. These biohorizons are traceable even though the LO of H. sellii is a diachronous event. Size variations of Gephyrocapsa from approximately 1250 ka are discussed and fluctuations of small size Gephyrocapsa could represent cyclic changes of the Kuroshio and Oyashio currents.

scholarly journals The lower Maastrichtian Hvidskud succession, Møns Klint, Denmark: calcareous nannofossil biostratigraphy, carbon isotope stratigraphy, and bulk and brachiopod oxygen isotopes.

2014 ◽  
Vol 62 ◽  
pp. 89-104
Author(s):  
Mads Engholm Jelby ◽  
Nicolas Thibault ◽  
Finn Surlyk ◽  
Clemens V. Ullmann ◽  
Rikke Harlou ◽  
...  
Keyword(s):  
Western Europe ◽  
Stratigraphic Correlation ◽  
Free World ◽  
Calcareous Nannofossil ◽  
Stratigraphic Framework ◽  
Lower Maastrichtian ◽  
Age Model ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Isotope Stratigraphy ◽  
North Western

A new calcareous nannofossil and δ13C stratigraphy is established for the chalk exposed in the lower Maastrichtian Hvidskud succession, Møns Klint, Denmark. It is based on 21 nannofossil samples and analysis of 82 stable isotope samples, allowing correlation with a previously established brachiopod zonation. The succession, which belongs to the brachiopod spinosa-subtilis to pulchellus-pulchellus zones, extends upwards from calcareous nannofossil subzone UC16ii to UC19ii and encompasses δ13C events M1+ to M2+. A new chronostratigraphic and geochronological age model is proposed based on correlation with the cored boreholes Stevns-1 (Denmark) and ODP Site 762C (Indian Ocean). Hvidskud encompasses the 405 kyr eccentricity cycles Ma40513 – Ma40511 within magnetochron C31r. A sedimentation rate of 5.0 cm kyr-1 can be inferred from correlation to geochronological tie-points in ODP 762C, suggesting an age of ~70.9 Ma for the base of the succession and a duration of >680 kyr for the investigated interval. The Hvidskud succession is well-exposed, easily accessible, and the new stratigraphic framework and precise age model suggest that it can be used as a key locality for stratigraphic correlation of the lower Maastrichtian in north-western Europe. Information on palaeo-seawater temperatures can be drawn from oxygen isotope records obtained from bulk rock samples and 24 micromorphic brachiopod specimens (Terebratulina faujasii). The brachiopod data show a clear diagenetic trend but point to an upper range of unaltered values between –0.4 and –0.6‰. Assuming a δ18O value of –1‰ for seawater in a Cretaceous ice-free world, this would indicate bottom water temperatures of 13.6 to 14.3°C of the Danish Chalk Sea (45°N) during the early Maastrichtian cooling.

scholarly journals Ostracods and foraminifera from the Early - Middle Eocene of Qeren Sartaba, Jordan Valley

1991 ◽  
Vol 10 (1) ◽  
pp. 95-107 ◽  
Author(s):  
A. Honigstein ◽  
A. Rosenfeld ◽  
C. Benjamini
Keyword(s):  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Early Eocene ◽  
Jordan Valley ◽  
Central Jordan ◽  
Species Groups ◽  
Foraminiferal Biostratigraphy

Abstract. 23 species of ostracods and 20 species and species groups of planktonic foraminifera from the 80m thick Qeren Sartabasection, central Jordan Valley, are described and illustrated. The material is determined by planktonic foraminiferal biostratigraphy to belong to the latest Early Eocene (upper part of Zone P9) and the early Middle Eocene (Zone P10). The palaeoecology is representative of a pelagic marine shelf, with periodic events of shallowing and hardground formation.

scholarly journals Upper Eocene planktonic foraminifera from northern Saudi Arabia: implications for stratigraphic ranges

2021 ◽  
Vol 40 (2) ◽  
pp. 145-161
Author(s):  
Bridget S. Wade ◽  
Mohammed H. Aljahdali ◽  
Yahya A. Mufrreh ◽  
Abdullah M. Memesh ◽  
Salih A. AlSoubhi ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Planktonic Foraminifera ◽  
Late Eocene ◽  
Calcareous Nannofossil ◽  
Upper Eocene ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Stratigraphic Ranges ◽  
Latest Eocene ◽  
Stratigraphic Range

Abstract. The Rashrashiyah Formation of the Sirhan Basin in northern Saudi Arabia contains diverse assemblages of planktonic foraminifera. We examined the biostratigraphy, stratigraphic range and preservation of upper Eocene planktonic foraminifera. Assemblages are well-preserved and diverse, with 40 species and 11 genera. All samples are assigned to the Priabonian Globigerinatheka semiinvoluta Highest Occurrence Zone (E14), consistent with calcareous nannofossil biostratigraphy indicating Zone CNE17. Well-preserved planktonic foraminifera assemblages from the lower part of the upper Eocene are rare worldwide. Our study provides new insights into the stratigraphic ranges of many species. We find older (Zone E14) stratigraphic occurrences of several species of Globoturborotalita previously thought to have evolved in the latest Eocene (Zone E15, E16) or Oligocene; these include G. barbula, G. cancellata, G. gnaucki, G. pseudopraebulloides, and G. paracancellata. Older stratigraphic occurrences for Dentoglobigerina taci and Subbotina projecta are also found, and Globigerinatheka kugleri occurs at a younger stratigraphic level than previously proposed. Our revisions to stratigraphic ranges indicate that the late Eocene had a higher tropical–subtropical diversity of planktonic foraminifera than hitherto reported.

scholarly journals Ichnofabrics of Eocene oil shales from central Jordan and their use for paleoenvironmental reconstructions

GeoArabia ◽  
2014 ◽  
Vol 19 (1) ◽  
pp. 85-112
Author(s):  
Mohammad Ali Hussein ◽  
Mohammad Alqudah ◽  
Olaf G. Podlaha
Keyword(s):  
Bottom Water ◽  
Middle Eocene ◽  
Trace Fossils ◽  
Total Thickness ◽  
Central Jordan ◽  
Depositional System ◽  
Rapid Changes ◽  
Oil Shales ◽  
Geochemical Studies ◽  
Paleoenvironmental Reconstructions

ABSTRACT The study of trace fossils is widely used in facies interpretation. It provides a crucial tool for reconstructing depositional paleoenvironments when used in combination with other sedimentological and paleontological proxies. Here we present the first detailed study of Eocene trace fossils from Jordan. Two sections of Early to Middle Eocene age, with a total thickness of 478.7 m, from central Jordan were cored and investigated. The results of individually occurring (isolated) or co-occurring (combined) ichnofabrics and bioturbation levels, in combination with results from biostratigraphic and geochemical studies, were used for stratigraphic and paleoenvironmental reconstructions. The bioturbation index (BI) was used to classify the burrowing density versus the preservation of the original sedimentary structures. The two cores show highly variable grades of bioturbation with BI ranging from 0 to 6. Four ichnogenera were identified: Thalassinoides, Chondrites, Teichichnus and Zoophycos. Both the ichnofabrics and the variations of the BI suggest a shallow, highly dynamic depositional system with rapid changes of water depth and degree of bottom-water oxygenation.

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