Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Cephalopods and Stratigraphical Position of Cephalopod Bed of Shishtu Formation, Iran

Document Type : Original Research Paper

Authors
Alireza Ashouri
Ahmad Yamini
Ferdowsi University of Mashhad, Mashhad, Iran
Abstract
This paper attempts to describe a cephalopod fauna from the "Cephalopod Beds" in the Shotori Range, Central Iran. The fauna contains 5 genera of nautiloid cephalopods and 12 genera of ammonoids. Among these, 7 ammonoid genera (Tornoceras, Cheiloceras, Maeneceras, Gonioclymenia, Cyrtoclymenia, Staffites, and Falcitornoceras) and 5 nautiloid genera (Ormoceras, Mooreoceras, Sycoceras, Michelinoceras, and Macroloxoceras) are reported for the first time from Iran. Ammonoid faunas indicate a Middle(?)/Late Frasnian to Late Famennian age for the "Cephalopod Beds", confirmed by conodont (Ashouri, 1990, 1995 & 1997) and brachiopod (Rastkar, 1996) studies.Microfacies analysis of the sections indicates that sedimentation occurred in a mostly shallow and high energy sedimentary environment. The distribution of goniatite fauna in eastern as well as northern Iran suggests similar paleobiological condition and a marine connection of the two regions during the Famennian stage. A paleogeographical map of the Late Devonian and comparison of the goniatite fauna of the study area with Alborz, Kazakhstan, China, North Africa and Europe indicate that these areas were in low latitudes during this time.
Keywords
Cephalopod Beds
Cephalopod
Shishtu Formation
Shotori Range
Iran

Subjects

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Scientific Quarterly Journal of Geosciences
Volume 15, Issue 60
Summer 2006, Vol. 15, No.60
Summer 2006
Pages 178-187