بررسی زیست چینه ای و پالئوژئوگرافی نهشته های آهکی دونین پسین در شمال و شمال غرب اسفراین به کمک مرجانها

Biostratigraphy and paleogeography of the Late Devonian limeston in north and northeast of Esfraien and corals

B. M. Kordghadimi, A. R.  Ashouri, K. Khaksar

Abstract

Corals are one of the main fossil group in the Late Devonian rocks in north and northeast of Esfaraien. Environmental sensitivity and lak of mobility factors in corals, make them excellent tools for paleogeographic and ecological zonation. Based on these general reasons, two ecological zone determinated in this study. The first one is related to near shore shallow water are composed of large and dissepimentary rugosa coral with Frasnian age and semiplagic basinal environment are composed small and solitary aulose's corals with Famennian age.The existence of  aulos's corals in  Late Devonian (Famennian) of study  area and  the presence of these spicese in other regions in the eastern Alborz, shows that a uniqe sea was coverd this region with similar conditioin.