Mesozoic radiolarians from the Kermanshah formation (Iran)

Radiolarites are one of the characteristic fades of the Tethyan Mesozoic realm. In western Iran, the Kermanshah radiolarites belong to a vast siliceous complex characteristic of the Mesozoic rocks of the Tethys region. These siliceous sequences are associated either with ophiolitic outcrops, which allow us to date them, or to sedimentary sequences that were deposited in a long and narrow basin in an intertropical zone, which benefited from the nutritional content of upwellings driven by monsoons. This basin extended from the Hawasina series (Oman) in the south, continued northward into the series of Pichakun (South Iran) and Kermanshah (western Iran) and ended with the Kocali series (Turkey). Radiolarites were dated in these different parts of the basin except in Kermanshah. The present work fills this gap and reveals that several levels can be dated by radiolarians from the Lower Pliensbachian, for the oldest ones, up until the Turonian for the youngest. (C) 2010 Academia des sciences. Published by Elsevier Masson SAS. All rights reserved.