Document Type : Research Paper
Authors
1
ssist. Prof., Department of Geology, Faculty of Sciences, University of Gonabad, Gonabad, Iran
2
Assist. Prof., Department of Geology, Faculty of Sciences, University of Gonabad, Gonabad, Iran
3
PhD Graduate, Central Laboratory Expert of Lorestan University, Khorramabad, Iran
Abstract
The aim of this research is the investigation of lithofacies and sedimentary environment of the Kashkan Formation (middle Eocene) in the Lorestan sedimentary basin. In this regard, four stratigraphic sections were selected. The Kashkan Formation in the studied area, with a variable thickness between 150 to 200 meters, consists of conglomerate, sandstone, and to a lesser extent fine-grained facies. Field studies on the four sections led to the identification of 12 lithofacies, which include five conglomeratic lithofacies (Gm, Gms, Gp, Gh, Gt), five sandstone lithofacies (Sp, St, Sm, Sh, Sr), and two mudstone lithofacies (Fm, Fl). Based on the vertical and lateral changes of facies, the depositional environment of these deposits was a braided river system with a gravelly and sandy bed in proximal areas. The clastic sequences of the Kashkan Formation overlie the marine carbonates of the Taleh Zang Formation, which indicates a sea regression and the progradation of braided rivers toward the basin. A decrease in accommodation space relative to sediment supply caused the progradation of braided river facies within the LST facies suite for the Kashkan Formation. Paleocurrent analysis in this formation shows a northeast to southwest trend, which is evidence of unidirectional (fluvial) currents in the Kashkan Formation.
Keywords
Main Subjects
)