Stratigraphy and larger benthic foraminifera of Middle Eocene to Middle Miocene rocks along the Tobruk-Al Bardia scarps, northeastern Cyrenaica, Libya

Stratigraphy ◽  
2018 ◽  
Vol 15 (3) ◽  
pp. 153-178
Author(s):  
Esam O. Abdulsamad ◽  
Salah S. El-Ekhfifi ◽  
Ahmed M. Muftah
Keyword(s):  
Benthic Foraminifera ◽  
Middle Miocene ◽  
Middle Eocene ◽  
Larger Benthic Foraminifera

scholarly journals SOKOLOWIA HORIZON OF THE ZIARAT FORMATION (EASTERN ALBORZ, IRAN): BIOSTRATIGRAPHIC AND PALEOGEOGRAPHIC IMPLICATIONS

2019 ◽  
pp. 15-27
Author(s):  
Mehdi Hadi ◽  
Amir Salahi ◽  
Yaghub Nasiri ◽  
Hossein Mosaddegh
Keyword(s):  
Central Asia ◽  
Tarim Basin ◽  
Genetic Relationship ◽  
Benthic Foraminifera ◽  
Middle Eocene ◽  
Southeastern Europe ◽  
Larger Benthic Foraminifera ◽  
Central Asian ◽  
Apparent Similarity ◽  
Eastern Central Asia

The present study deals with molluscan accumulations of the Sokolowia horizon, which is a key-bed in the middle Eocene of the Kalateh section (Ziarat Formation, Eastern Alborz, Iran). The age of this “key horizon” is at-tributed to Bartonian based on presence of larger benthic foraminifera species such as Nummulites lyelli (D'Archiac & Haime), Orbitoclypeus zitteli (Checchia-Rispoli) and Asterocyclina stella stella (Gümbel) immediately below it. The paleogeographic distribution of Sokolowia occurrence from Tarim Basin in eastern Central Asia to the Transylvanian Basin in southeastern Europe indicates a middle Eocene seaway along the southern margin of an Eurasian epicontinental sea. In particular, the comparison of middle Paleogene sequences in different Central Asian regions reveals an apparent similarity between those basins pointing to their genetic relationship.

The incidence of unusual test morphologies of Eocene Larger benthic foraminifera: An example of Paleogene Adriatic Carbonate Platform

2021 ◽  
Author(s):  
Vlasta Ćosović ◽  
Jelena Španiček ◽  
Katica Drobne ◽  
Ervin Mrinjek
Keyword(s):  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Middle Eocene ◽  
Morphological Diversity ◽  
Late Eocene ◽  
Early Eocene ◽  
Coralline Red Algae ◽  
Larger Benthic Foraminifera ◽  
Shallow Marine ◽  
Scientific Project

<p>The Paleogene Adriatic carbonate platform(s) existed within the Central NeoTethys (around 32 N paleolatitude) from the Danian to the late Eocene (Bartonian/Priabonian) and produced a succession of limestones up to 500 m thick, rich in larger benthic foraminifera (LBF). The Eocene sediments are widely distributed along the eastern Adriatic coast and have been studied for many years. Taking into account the climatic changes that took place within the Eocene (Early Eocene and Middle Eocene climatic optima, known as EECO, MECO), special attention was paid to the composition of shallow-marine foraminiferal assemblages. The studies reveal the following trends: (1) the alveolinid-dominated assemblages were replaced by nummulitid-dominated assemblages around the MECO; (2) the greater species and morphological diversity (spherical, ellipsoid, extremely elongated fusiform) of the alveolinid fauna was evident at the EECO; (3) the nummulitid-dominated fauna was characterized by less diversified assemblages compared to the alveolinid ones and by the co-occurrence of scleractinian corals, coralline red algae and aborescent foraminifera. The occurrence of twin embryos has been assigned to the early Eocene in the alveolinid populations, especially in Alveolina levantina and A. axiampla (in some sections, the frequency is greater than 5%), and these coalesced embryos have the same size as the single form (usually they are smaller). The LBF assemblages of Middle Eocene showed a greater frequency of doubled adult tests (Orbitolites sp., Nummulites sp.). The origin of these unusual morphologies is poorly known, usually described as the results of stressful conditions. Considering the timing of the appearance of such morphologies, temperature and associated changes in the shallow-marine environment could be the cause.</p><p>This study is carried out as part of the scientific project IP-2019-04-5775 BREEMECO, funded by Croatian Scientific Foundation.</p>

scholarly journals Neorotalia omanensis and Operculina musawaensis from the Sultanate of Oman

2013 ◽  
Vol 18 ◽  
pp. 41
Author(s):  
Abdul Razak Siddiq Al-Sayigh
Keyword(s):  
New Species ◽  
Middle East ◽  
Benthic Foraminifera ◽  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Early Eocene ◽  
Sultanate Of Oman ◽  
Larger Benthic Foraminifera ◽  
Oman Mountains ◽  
Two New Species

Two new species of larger benthic foraminifera, Neorotalia omanensis n. sp. and Operculina musawaensis n. sp. are described and illustrated from the eastern Oman Mountains. N. omanensis n. sp. occurs in the Musawa Formation in association with the planktonic foraminifera Morozovella edgari and Truncarotaloides topilensis indicating an early to middle Eocene age (P10-P13). Operculina musawaensis n. sp. occurs in the Abat Formation in association with the planktonic foraminifera Acarinina esnaensis and A. soldadensis indicating an early Eocene age (P6).  This is the first known record showing the presence of genus Neorotalia in the Middle East. Representatives of the larger foraminiferal genus Linderina sp. are also described and illustrated from the Musawa Formation and compared with the published Linderina species in the surrounding countries.  

Selectivity of foraminiferal extinction in the late Eocene

Paleobiology ◽  
1997 ◽  
Vol 23 (3) ◽  
pp. 347-357 ◽  
Author(s):  
Amit Banerjee ◽  
George E. Boyajian
Keyword(s):  
Benthic Foraminifera ◽  
Middle Eocene ◽  
Late Eocene ◽  
Mass Extinctions ◽  
Larger Benthic Foraminifera ◽  
Late Paleocene ◽  
Risk Of Extinction ◽  
Extinction Event

Late Eocene foraminiferal extinction shows diverse patterns of selective morphologic and latitudinal extinction. Taxa with discoidal shape, calcareous tests, and narrow and low-latitudinal ranges are at significantly greater risk of extinction. Elevated extinction intensities in calcareous tests are mainly due to the presence of larger benthic foraminifera that evolved in late Paleocene and diversified through the lower to middle Eocene. Selectivity of late Eocene foraminiferal extinction indicates that this extinction event was not a globally uniform event. Although this result does not verify an extraterrestrial impact or any other proposed cause of extinction, it does constrain the causes of late Eocene extinction. Furthermore, the geography of late Eocene foraminiferal extinction, and previously studied Cenomanian/Turonian extinction, demonstrates that mass extinctions exhibit different patterns of selectivity.

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