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 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.

scholarly journals UPPER EOCENE CALCAREOUS NANNOFOSSIL BIOSTRATIGRAPHY: A NEW PRELIMINARY PRIABONIAN RECORD FROM NORTHERN SAUDI ARABIA

2020 ◽  
Vol 18 (4) ◽  
pp. 5607-5625
Author(s):  
M.H. ALJAHDALI ◽  
M. ELHAG ◽  
Y. MUFRREH ◽  
A. MEMESH ◽  
S. ALSOUBHI ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Calcareous Nannofossil ◽  
Upper Eocene ◽  
Calcareous Nannofossil Biostratigraphy

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.

Truncorotaloides danvillensis (Howe and Wallace), new generic assignment for a Late Eocene planktonic species of Foraminiferida

1986 ◽  
Vol 60 (2) ◽  
pp. 539-541
Author(s):  
Woodson M. Godfrey ◽  
Willem A. van den Bold
Keyword(s):  
Planktonic Foraminifera ◽  
Late Eocene ◽  
Upper Eocene ◽  
Planktonic Species

Globorotalia danvillensis was described by Howe and Wallace (1932) from beds at Danville Landing on the Ouachita River, Louisiana. Fisk (1938) gave these beds formational status, because he considered them to be a mappable unit, representing the uppermost Eocene deposits in Louisiana. These beds are placed in the Globorotalia cerroazulensis s.l. Zone. Globorotalia danvillensis was later reported by Bergquist (in Bergquist and McCutcheon, 1942) from upper Eocene beds in Mississippi. The present authors have found the same species in beds of the Lower Jackson Group at Montgomery Landing, Louisiana, which include the upper part of the Porticulasphaera semiinvoluta Zone and the lower part of the Globorotalia cerroazulensis Zone. During the investigation it was found that the species exhibits small, secondary, sutural apertures on the spiral side, which places it in the genus Truncorotaloides Brönnimann and Bermúdez (1953). Howe (1939), in his study of the Cook Mountain foraminifera, followed the custom of that time (see Cushman and Dusenbury, 1934, p. 63) of tentatively referring small coiled species of planktonic foraminifera to Globigerina cretacea d'Orbigny. Re-examination of samples from the Cook Mountain Formation of Saline Bayou, Winn Parish, Louisiana (H. V. Howe collection M 524–527) reveals that many of Howe's specimens belong to Truncorotaloides danvillensis. This species occurs here together with T. rohri Brönnimann and Bermúdez.

scholarly journals Calcareous Nannofossil Biostratigraphy and Ostracoda Paleoecology of Hartha Formation from Balad (1) well, Central Iraq

2021 ◽  
pp. 3962-3972
Author(s):  
Omar Ahmed Al-Badrani ◽  
Faris Nejris Hassan ◽  
Mahfoudh Abdulla Al-Hadeedy
Keyword(s):  
Continental Shelf ◽  
Outer Shelf ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Inner Shelf ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Stratigraphic Ranges

Seventeen samples of Hartha Formation in Balad (1) well, central Iraq, are studied on the basis of stratigraphic ranges of the recorded calcareous nannofossils for twenty species belonging to twelve genera. The studied section reveals three biozones arranged from oldest to youngest as follows; (1) Calculites ovalis Interval Biozone (CC19), (2) Ceratolithoides aculeus Interval  Biozone (CC20), (3) Quadrum  sissinghii Interval Biozone (CC21). These Biozones are correlated with other calcareous nannofossils biozones from both local and regional sections, leading to conclude the age of the Middle Campanian. Rerecorded eighteen ostracode species that belong to eleven genera are identified, all of which were previously recorded from Iraq and adjacent regions. The occurrence of these species leads to conclude a continental shelf environment, while they are typical of inner shelf-outer shelf depth.

Additional records of Collinsius simplex (Brachyura, Chasmocarcinidae) from the Upper Eocene to Lower Oligocene strata in Kyushu (Japan), and description of a new species of ghost shrimp (Axiidea, Callichiridae)

2020 ◽  
Vol 296 (1) ◽  
pp. 9-18
Author(s):  
Yusuke Ando
Keyword(s):  
New Species ◽  
Late Eocene ◽  
Middle Part ◽  
Calcareous Nannofossil ◽  
Upper Eocene ◽  
Lower Margin ◽  
Ghost Shrimp ◽  
Lower Oligocene ◽  
South West ◽  
A New Species

Additional specimens of Collinsius simplex Karasawa, 1993, a species first described from the Kishima Formation (Lower Oligocene, uppermost part of calcareous nannofossil zone CP16a), are recorded from the Upper Eocene– Lower Oligocene (CP15b– CP16a) Funazu Formation (Iojima Group) and the Lower Oligocene (CP16b) Itanoura Formation (Nishisonogi Group) in Kyushu, south- west Japan. This material extends the stratigraphical range of Collinsius simplex further back into the Late Eocene. In addition, a new species of ghost shrimp, Vecticallichirus kawanoi sp. nov., is described from the middle part of the Funazu Formation (Upper Eocene). This has a blade with ap- proximately 10 serration- like spines on the lower margin of the merus, a long carpus with an unarmed margin and a molar- like triangular tooth proximally on the occlusal margin near the base of fixed finger. It appears closest to V. batei (Woodward 1869), but differs in that the carpus has an unarmed lower margin; the same holds true for the fixed finger.

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