Biostratigraphy and Lithostratigraphy of Chaman Bid Formation in type locality and first presentation of several genus and species of ammonite in Iran

Category Paleontology and Stratigraphy
Group GSI.IR
Location 23th symposium on geosciences
Holding Date 05 May 2008

      In contrast to the 1722 m measured by Afshar Harb (1994) 1556 m were measured here. The Chaman Bid Formation mostly consists of alternations of grey limestone, grey marly limestone (mudstone to packstone) with pyrite, shale, argillaceous shale, and a few levels of sandstones. According to the ammonite fauna, the Chaman Bid Formation ranges from the ?Bathonian to the Tithonian. At the type locality, the formation has been subdivided, from base to top, into seven members.
   Some of the ammonite genera and species are recorded from Iran for the first time. These include Phanerostephanus subsenex, Nothostephanus sp., Nannostephanus cf. subcomutus, Richterella richteri, Pseudolissoceras zitteli, Glochiceras sp., Oxylenticeras cf. lepidum.
   Based on ammonites, the Chaman Bid Formation ranges from the the ?Bathonian to Lower Tithonian in Chaman Bid section.
   Open-marine environments of the Chaman Bid Formation was separated from the extensive shelf lagoon by a rimmed platform margin. Their sediments were deposited on the slope of the carbonate platform and in the adjacent basin.