TITLE:
Interpretation of Depositional Environment of Fusulinid Bearing Middle Permian Succession of Bolula and Khaja Ghar Formation, Bamian Zone, Central Afghanistan
AUTHORS:
Mohammad Naeem Sarwary, Chaman Shah Alamy, Mohammad Ltif Rahimi, Pramod Kumar
KEYWORDS:
Permian of Afghanistan, Bolula and Khajagarh Formation, Fusulinid Foraminifera, Depositional Environments, Paleogeographic Significance
JOURNAL NAME:
International Journal of Geosciences,
Vol.13 No.7,
July
19,
2022
ABSTRACT: The study area belongs to the
north Afghanistan having complex tectonic setting, because
of separation of the Afghanistan plate from Pangea in Early Permian and its
subsequent northward journey and collision with Eurasian plate. The rock
exposed in the area belongs to Paleozoic, Mesozoic to Quaternary with
Proterozoic basement. Particularly the Permian succession of Afghanistan is
rich in fusulinids (larger foraminifera), is age
diagnostic, provides strong biostratigraphic tool for the Permian deposits, and has paleobiogeographic applications. The Bamian zone of north
Afghanistan has good exposure to Middle Permian and is designated as Bolula and
Khaja Ghar Formation is undertaken in this study. The Bolula Formation overlies
the greenschist and basalts, composed mainly of carbonate rocks (Dolostone and
limestone), having massive limestone, with some quartz and secondary calcite
vein in the succession. The intermittent siliciclastic wedges within the
carbonate succession are identified as input within the platform with tectonic
pulses in the hinterland. Bolula and Khaja Ghar succession is divided into 8
lithofacies ( Facies A to H) and 6 carbonate Facies viz. Sparry calcites
limestone, Micritic limestone, Fossiliferous limestones (Biomicrite), Peloidal
limestone (Fecal pellets), Interlaminated micritic and sparite limestone, and sandy
limestone (micritic). The Bolula and Khaja Ghar Formation in the Bamian area
have deposited in a shallow marine shelf environment because of predominance of
carbonate rocks and presence of shallow-water marine fossils including fusulinids,
small benthic foraminifera, algae, bivalve, brachiopods fragments, corals and
bryozoans, etc. In the Bamian zone the unconformity between Upper Carboniferous
and Lower Permian; indicates extensive gap in sedimentation, traceable to many
parts of Afghanistan as unconformity or tectonic contact is considered here as
sequence boundary.