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

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.

2021 ◽  
Author(s):  
◽  
John R. Lavas

<p>The subclass Archosauria includes some of the most successful vertebrates to have evolved. Although traditionally viewed as 'cold-blooded' (= ectothermic) and therefore evolutionarily inferior to 'warm-blooded' (= endothermic) mammals and birds, data collected since the 1960s has resulted in significant re-evaluations and a complete reassessment of archosaur evolution, taxonomy, and inferred physiology and behaviour. Much of the relevant data emanates from the results of post WWII field work conducted in eastern Central Asia (particularly the Gobi Desert) by Russian, Polish and Mongolian palaeontologists. However, due to political, cultural and/or other reasons, there remained little scientific collaboration between them and western (particularly US) scientists until very recently. As a consequence, there developed a dichotomy in this field of archosaur research, not only between east and west, but also between Europe and the US. This thesis reviews the literature on archosaurs published world-wide from Jan 1960 - Dec 1984, with the emphasis on the important Central Asian/Gobi contributions, in order to evaluate the academic discussions that have arisen regarding archosaur evolution, physiology, behaviour, their relationship to the Aves, and the evolution of avian endothermy and flight.</p>


2021 ◽  
Author(s):  
Vlasta Ćosović ◽  
Jelena Španiček ◽  
Katica Drobne ◽  
Ervin Mrinjek

&lt;p&gt;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.&lt;/p&gt;&lt;p&gt;This study is carried out as part of the scientific project IP-2019-04-5775 BREEMECO, funded by Croatian Scientific Foundation.&lt;/p&gt;


2017 ◽  
Vol 80 (2) ◽  
pp. 339-363 ◽  
Author(s):  
Tomas Larsen Høisæter

AbstractThe Silk Road trade network was arguably the most important network of global exchange and interaction prior to the fifteenth century. On the question of how and when it developed, scholars have focused mainly on the role of either the empires dominating the two ends of the trade network or the nomadic empires on the Eurasian steppe. The sedentary people of Central Asia have, however, mostly been neglected. This article traces the development of the city-states of the Tarim Basin in eastern Central Asia, from c. 2000 bce to 400 bce. It argues that the development of the city-states of the Tarim Basin is closely linked to the rise of the ancient Silk Road and that the interaction between the Tarim polities, the nomads of the Eurasian steppe and the Han Empire was the central dynamic in the creation of the ancient Silk Road network in eastern Central Asia.


2021 ◽  
Author(s):  
◽  
John R. Lavas

<p>The subclass Archosauria includes some of the most successful vertebrates to have evolved. Although traditionally viewed as 'cold-blooded' (= ectothermic) and therefore evolutionarily inferior to 'warm-blooded' (= endothermic) mammals and birds, data collected since the 1960s has resulted in significant re-evaluations and a complete reassessment of archosaur evolution, taxonomy, and inferred physiology and behaviour. Much of the relevant data emanates from the results of post WWII field work conducted in eastern Central Asia (particularly the Gobi Desert) by Russian, Polish and Mongolian palaeontologists. However, due to political, cultural and/or other reasons, there remained little scientific collaboration between them and western (particularly US) scientists until very recently. As a consequence, there developed a dichotomy in this field of archosaur research, not only between east and west, but also between Europe and the US. This thesis reviews the literature on archosaurs published world-wide from Jan 1960 - Dec 1984, with the emphasis on the important Central Asian/Gobi contributions, in order to evaluate the academic discussions that have arisen regarding archosaur evolution, physiology, behaviour, their relationship to the Aves, and the evolution of avian endothermy and flight.</p>


Author(s):  
Abdul Razak Siddiq Al-Sayigh

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.  


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