The Ordovician of the Middle East (Iran, Afghanistan, Pakistan)

Abstract

Abstract Ordovician studies in Iran have shown significant progress since the beginning of the century. A number of individual faunas have been documented and a biostratigraphical framework based on conodonts, chitinozoans, acritarchs and trilobites developed. Correlation of Ordovician successions with the International Chronostratigraphic Chart has been significantly improved, and the position of the series and stage boundaries can be recognized with greater precision. While geographical proximity to temperate latitude Gondwana is apparent for most Iranian terranes, biogeographical links of Alborz and Kopet-Dagh with South China prevailed through the Early–Middle Ordovician. In Pakistan, Ordovician deposits have a restricted distribution in the Karakorum block (Chitral). Here they are represented by the Yarkhun and Vidiakot formations with Floian–Darriwilian acritarchs, chitinozoans and early Darriwilian conodonts. In Peshawar District of the North-West Frontier Province, an Early–Middle Ordovician age is likely for the Misri Banda Quartzite with Cruziana rugosa trace fossils. It is overlain conformably by carbonates of the Panjpir Formation, which has an inferred Middle Ordovician–Silurian age. Presently available information on the Ordovician of Afghanistan is mostly based on reconnaissance studies performed almost half a century ago, and a few monographed Early and Late Ordovician faunas.