Reconnaissance geology in Upper Chitral,Baroghil and Karambar districts (northern Karakorum,Pakistan) |
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Authors: | Maurizio Gaetani Lucia Angiolini Alda Nicora Dario Sciunnach Patrick Le Fort Seifnullah Tanoli Asif Khan |
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Institution: | (1) Dipartimento di Scienze delta Terra, Università di Milano, Via Mangiagalli 34, I-20133 Milan, Italy;(2) LGCA-UPRES-A No. 5025 CNRS, Université Fourier, Grenoble, France;(3) Centre of Excellence in Geology and University of Peshawar, Peshawar, Pakistan |
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Abstract: | During the summer of 1992 a geological expedition crossed the northern Karakorum range in northern Pakistan, from the Chitral
to Karambar valleys, from the villages of Mastuj to Imit. Some of the areas visited were geologically unknown. A number of
structural units were crossed, belonging to the Karakorum block or to other crustal blocks north of it. They are: (a) the
axial batholith, in which three plutonic bodies have been identified, and (b) the northern sedimentary belt (NSB), in which
three major tectonostratigraphic units form thrust stacks dipping to the north. Their internal stratigraphy and structural
style are partly different. The most complete contains a crystalline basement, transgressed by a marine succession during
the Early Ordovician. The youngest strata are represented by the Reshun conglomerate, of inferred Cretaceous age. The northernmost
unit of the NSB is tightly folded, whereas the central one forms a monocline. Vertical faults, mainly strike-slip, dissect
the thrusted slabs. Metamorphic deformation is absent or reaches only the anchizone in the studied sector of the Karakorum
NSB. To the north of the Karakorum proper there are several other tectonic units, separated by vertical faults. They are,
from south to north: (a) the Taš Kupruk zone, with metavolcanics of basaltic to latibasaltic composition; (b) the Atark unit,
mostly consisting of massive carbonate rocks of Mesozoic age; and (c) the Wakhan slates which consist of a thick widespread
succession of dark slates, metasiltites and sandstones. The fine-grained elastic rocks are supposed to be Palaeozoic to Early
Triassic in age. The Wakhan slates are intruded by plutons belonging to the East Hindu Kush batholith, from which a single
K/Ar age on muscovite gave a Jurassic age. |
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Keywords: | General geology Stratigraphy Magmatism Volcanism Structure Karakorum Central Asia Pakistan |
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