Document Type : Original Research Paper
Authors
1 M. Sc. Student, Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
2 Assistant Professor, Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
3 Ph. D., Geological Survey of Iran, Tehran, Iran
Abstract
The Farrokhi formation in 15 km southwest of Khur with a thickness of up to 117m consists of marl and limestone with Maastrichtian age. In this section, the Farrokhi formation disconformably overlies the Haftoman formation below and the Chupanan formation above. In the present study, 87 genera and 103 species have been recognized. Based on foraminifera, the Farrokhi formation ranges from the Maastrichtian and 3 biozones in the rock unit 1 of the formation have been recognized: (1) Contusotruncana contuse Partial range zone (CF6), indexing Early Maastrichtian.(2) Pseudotextularia intermedia Partial range zone (CF5), index for late Early Maastrichtian index and (3) Racemiguembelin fructicosa Taxon Range Zone (CF4), an index for early Late maastrichtian. The Farrokhi formation can be subdivided into four rock units which are composed of marl and marly limestone. In addition, the Farrokhi formation fauna contains ostracods and high abundance of invertebrate as diverse species of brachiopods, echinoderms and bivalves with rare fragments of ammonites. The K/Pg boundary is in this section paraconform and can be compared with boundary of the Farrokhi and Chupanan formations. The evidence of paraconformity is a gap of Early Paleocene and changes in lithfacies. The Farrokhi formation is carbonate and it is parts of a carbonate system consisting of a platform and the adjacent slope.
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