Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Lithostratigraphy, Microbiostratigraphy and Microfacies of the Ilam Formation in Southwestern Khorram Abad

Document Type : Original Research Paper

Authors
S.H. Vaziri 1
D. Jahani 1
M. Safdari 2
F. Chegeni 2
1 Department of Geology, Faculty of Basic Sciences, Islamic Azad University, North Tehran Branch.
2 Department of Geology, Faculty of Basic Sciences, Islamic Azad University, Khorram Abad Branch.
10.22071/gsj.2009.57824
Abstract
       The Ilam Formation in southwestern Khorram Abad with a thickness of up to 204 meters consists of uniform limestones with Middle Turonian to Early Campanian age which were deposited in a continuous sedimentation process. In this section, the Ilam Formation has continuous and transitional contacts with the Sourgah Formation in the lower boundary and the Gurpi Formation in the upper boundary. In the present study, 9 genera, 30 species and 2 biozones of the planktonic foraminifera have been recognized. The Ilam Formation in the studied section consists of a shaly facies and three carbonatic microfacies include mudstone, wackestone and packstone containing planktonic foraminifera. Shaly facies and mentioned microfacies were deposited in deep-open marine, which formed in a quiet environmental condition and increased environmental energy in microfacies with mudstone texture toward microfacies with wackestone and packstone textures. Whereas in the studied section recognized microfacies are not related to parts of continental shelf,such as ; bar, lagoon and tidal flat, therefore it could be said that, the studied area was part of profound depositional basin in Middle Turonian to Early Campanian.
Keywords
Ilam Formation
Turonian
Campanian
Biozonation
Microfacies
Khorram Abad
 
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Scientific Quarterly Journal of Geosciences
Volume 17, Issue 67
Winter 2008
Pages 124-139