UPPER TRIASSIC (NORIAN) CEPHALOPODS FROM THE EKRASAR FORMATION (SHEMSHAK GROUP) OF NORTHERN ALBORZ, IRAN

Autor: KAZEM SEYED-EMAMI, FRANZ THEODOR FÜRSICH, MARKUS WILMSEN, MAHMOUD REZA MAJIDIFARD, ALI SHEKARIFARD
Jazyk: angličtina
Rok vydání: 2009
Předmět:
Zdroj: Rivista Italiana di Paleontologia e Stratigrafia, Vol 115, Iss 2 (2009)
Druh dokumentu: article
ISSN: 0035-6883
2039-4942
DOI: 10.13130/2039-4942/6378
Popis: The following ammonoid and nautiloid taxa are described for the first time from the Upper Triassic succession (Ekrasar Formation, Shemshak Group) of northern Alborz, Iran: Arcestes sp., Arcestes (Pararcestes?) sp., Thisbites cf. agricolae Mojsisovics, Stikinoceras cf. kerri Mc Learn, Giesbachites sp., Griesbachites cf. pseudomedleyanus Diener, Griesbachites cf. himalayanus Wang & He, and Proclydonautilus? sp. Palaeobiogeographically, the studied ammonoids are Tethyan in character, and stratigraphically attributed to the lower Lower Norian (Guembelites jandianus Zone, possibly also Malayites paulckei Zone). The biostratigraphic data of this study demonstrate the diachronous base of the Shemshak Group: it is older in the northern Alborz (lower Lower Norian), but younger in Central Iran and probably also in the southern Alborz (Middle Norian).
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