TITLE:
Sequence Stratigraphy of Lower Carboniferous Rocks in Bakhshi Section, East-Central Iran
AUTHORS:
Soheil Erfani, Mohammad Hossein Adabi, Mahmood Reza Majidifard, Nader Kohansalghadimvand, Bibihaniyeh Emraninasab
KEYWORDS:
Lower Carboniferous, Kalmard Block, Gachal Formation, Sequence Stratigraphy
JOURNAL NAME:
Open Journal of Geology,
Vol.7 No.2,
February
27,
2017
ABSTRACT: The deposits of Lower Carboniferous rocks in
Kalmard Block are characterized by Gachal informal formation, showing various
properties in different outcrops. These deposits (in Gachal formation) are
composed chiefly of carbonate, evaporite and siliciclastic
rocks. This formation commonly hosts 190 m sandstone, limestone, dolomitic
limestone and dolomite as well as a small amount of shale and marl in the
Bakhshi section. It unconformably underlies
Devonian deposits (Rahdar formation) while lateritic soils of lower Permian
(Chili formation) are depicted overlying an erosional unconformity above this
formation. The mixed carbonate-evaporite-siliciclastic sequence of Gachal
formation is made up of three third-order depositional sequences, separated
from each other by Type 1 sequence boundary (SB1). Siliciclastic and evaporite
deposits include LST system tract, whereas carbonate microfacies involve TST
and HST system tracts, separated from each other by MFS. The depositional sequences identified in Gachal formation point to the Lower Carboniferous age, conforming to
upper Kaskaskia supersequence. The upper erosional boundary between
Gachal and Chili formations complies with the global-scale
sea level fall.