The first report of cryptospore assemblages of Late Ordovician in Iran, Ghelli Formation, Eastern Alborz

Abstract

For the first time, an assemblage of cryptospores, which includes 10 species belonging to nine genera, from the Upper Ordovician<br />strata, is being reported, in Iran. These cryptospore assemblages were recovered from the upper part of Ghelli Formation., from the<br />eastern Alborz Mountain range. These peri-Gondwanan cryptospores have been classified based on their morphology (monad, true<br />dyad, pseudodyad, true attached, and loose tetrads). The results of the present study support previous findings that there are no<br />significant differences between similar-aged cryptospore assemblages of the peri-Gondwanan, Baltic provinces and other parts of the<br />world. Based on the presence of the chitinozoan index of the northern Gondwana (Spinachitina oulebsiri), the index acritarchs, and the<br />present cryptospores, a late Hirnantian (Late Ordovician) age is proposed to the top of the Ghelli Formation. The cryptospores seem to<br />be transported from an adjacent land area and the lack of land-derived elements in the up-section may indicate an increased distance<br />offshore.