Facies analysis of a large-scale Jurassic shelf-lagoon: The Kamar-e-Mehdi formation of east-central Iran

Journal article


Publication Details

Author(s): Wilmsen M, Fürsich F, Seyed-Emami K, Majidifard MR, Zamani-Pedram M
Journal: Facies
Publication year: 2010
Volume: 56
Journal issue: 1
Pages range: 59-87
ISSN: 0172-9179
Language: English


Abstract


The Callovian-Lower Kimmeridgian Kamar-e-Mehdi Formation of the Tabas Block (east-central Iran) is an up to 1,350-m-thick, fine-grained, marly-calcareous unit containing a basal Echellon Limestone Member (up to 180 m thick) and a terminal Nar Limestone Member (up to 100 m thick). The formation was deposited in a relatively deep shelf-lagoon that was part of the large-scale carbonate system of the Esfandiar Subgroup, extending N-S for about 500 km along the strike with a width of up to 100 km. The lagoonal Kamar-e-Mehdi Formation shows sedimentation rates of 150 m/myr, twice as high as those of the shelf-edge carbonate barrier (Esfandiar Platform). The repetitive lithologies and uniform depositional environment suggest equilibrium conditions between sedimentation and subsidence, related to constant slow rotation of the Tabas fault-block around a horizontal axis, the platform sitting on the crest, and the lagoon occupying the dip-slope. Lagoonal sedimentation was dominated by suspended carbonate mud and peloids from the eastern Esfandiar Platform whereas the subordinate siliciclastic material was derived from the west (Yazd Block). The diverse macrobenthos (mainly bivalves) suggests fully marine conditions for the major part of the Kamar-e-Mehdi Formation. However, towards the upper part, biotic impoverishment and the deposition of skeletal-poor, evaporitic sediments indicate increasing restriction. The overlying Magu Gypsum Formation marks the end of an arid basin-fill cycle and possibly forms an effective seal for hydrocarbon reservoirs in that area. The Esfandiar Subgroup was a Neotethys-facing carbonate margin, forming part of a belt of carbonate systems tracking the margins of the Iran Plate during Callovian to Late Jurassic times. © 2009 Springer-Verlag.



FAU Authors / FAU Editors

Fürsich, Franz Prof. Dr.
Naturwissenschaftliche Fakultät
Wilmsen, Markus PD Dr.
Naturwissenschaftliche Fakultät


External institutions with authors

University of Tehran


How to cite

APA:
Wilmsen, M., Fürsich, F., Seyed-Emami, K., Majidifard, M.R., & Zamani-Pedram, M. (2010). Facies analysis of a large-scale Jurassic shelf-lagoon: The Kamar-e-Mehdi formation of east-central Iran. Facies, 56(1), 59-87. https://dx.doi.org/10.1007/s10347-009-0190-8

MLA:
Wilmsen, Markus, et al. "Facies analysis of a large-scale Jurassic shelf-lagoon: The Kamar-e-Mehdi formation of east-central Iran." Facies 56.1 (2010): 59-87.

BibTeX: 

Last updated on 2018-10-08 at 22:23