Naslov
Palorbitolina lenticularis from the northern Adriatic region : Palaeogeographycal and evolutionary implications

Autori
Husinec, Antun

Izvornik
Journal of foraminiferal research (0096-1191) 31 (2001), 4; 287-293

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Palorbitolina lenticularis; Aptian; palaeogeography; Adriatic; Croatia

Sažetak
Palorbitolina bearing samples were obtained from three localities on the islands of Cres and Lošinj in the northern Adriatic. Although a relatively small number of specimens are studied (less than 60), the size of the embryonic chamber and test diameters of Palorbitolina lenticularis indicate a Lower Aptian age. This is confirmed for the Adriatic carbonate platform by the presence of Lower Aptian index taxa. Both embryonic chamber and test diameter variation are pronounced. No change has been observed concerning the relationship between stratigraphic horizon and the embryonic chamber diameter. A proportional relationship between the size of the embryonic chamber and the test is determined. These data show that the predominately mixed clastic-carbonate environments of the Mediterranean were colonized by palorbitolinas before the Adriatic carbonate platform, as has been suggested by Velić & Sokač (1978). Although an essentially westwards water circulation during the late Barremian and early Aptian probably aided the colonization of the Tethyan realm by palorbitolinas, it can neither explain the simultaneous existence of palorbitolinas in different and remote parts of the Tethys nor their dispersal, which must have been very rapid.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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