A Periglacial Palaeoenvionment in the Upper Carboniferous–Lower Permian Tobra Formation of the Salt Range, Pakistan |
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作者姓名: | Irfan U. JAN Shahid IQBAL Sarah J. DAVIES Jan A. ZALASIEWICZ Michael H. STEPHENSON Michael WAGREICH Muhammad HANEEF Muhammad HANIF Sajjad AHMAD |
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基金项目: | This study benefited from the Higher Education Commission of Pakistan’s National Research Program for Universities (NRPU) grant to Dr. Irfan U. Jan, principal investigator on the project via grant number 20-2706. M. H. Stephenson publishes with the permission of the Director of the British Geological Survey (NERC). IGCP 609 support is also acknowledged. |
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摘 要: | The Upper Carboniferous—Lower Permian(Upper Pennsylvanian-Asselian) Tobra Formation is exposed in the Salt and Trans Indus ranges of Pakistan.The formation exhibits an alluvial plain(alluvial fan-piedmont alluvial plain) facies association in the Salt Range and Khisor Range.In addition,a stream flow facies association is restricted to the eastern Salt Range.The alluvial plain facies association is comprised of clast-supported massive conglomerate(Gmc),diamictite(Dm)facies,and massive sandstone(Sm) Hthofacies whereas the stream flow-dominated alluvial plain facies association includes fine-grained sandstone and siltstone(Fss),fining upwards pebbly sandstone(Sf),and massive mudstone(Fm) Hthofacies.The lack of glacial signatures(particularly glacial grooves and striatums) in the deposits in the Tobra Formation,which are,in contrast,present in their timeequivalent and palaeogeographically nearby strata of the Arabian peninsula,e.g.the AI Khlata Formation of Oman and Unayzah B member of the Saudi Arabia,suggests a pro-to periglacial,i.e.glaciofluvial depositional setting for the Tobra Formation.The sedimentology of the Tobra Formation attests that the Salt Range,Pakistan,occupied a palaeogeographic position just beyond the maximum glacial extent during Upper Pennsylvanian-Asselian time.
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关 键 词: | Pennsylvanian–Asselian Tobra Formation Salt Range Khisor Range glaciofluvial Pakistan |
收稿时间: | 2015/11/16 0:00:00 |
修稿时间: | 2016/4/5 0:00:00 |
A Periglacial Palaeoenvionment in the Upper Carboniferous–Lower Permian Tobra Formation of the Salt Range,Pakistan |
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Authors: | Irfan U JAN Shahid IQBAL Sarah J DAVIES Jan A ZALASIEWICZ Michael H STEPHENSON Michael WAGREICH Muhammad HANEEF Muhammad HANIF and Sajjad AHMAD |
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Institution: | 1 National Centre of Excellence in Geology, University of Peshawar, Pakistan,2 Department of Earth Sciences, Quaid-i-Azam University Islamabad, Pakistan, 45320
3 Department of Geodynamics and Sedimentology, University of Vienna, Austria,4 Department of Geology, University of Leicester, University Road Leicester, LE1 7RH, UK,4 Department of Geology, University of Leicester, University Road Leicester, LE1 7RH, UK,5 British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK,3 Department of Geodynamics and Sedimentology, University of Vienna, Austria,6 Department of Earth Sciences Comsats Institute of Technology, Abbottabad,1 National Centre of Excellence in Geology, University of Peshawar, Pakistan and 7 Department of Geology, University of Peshawar |
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Abstract: | The Upper Carboniferous–Lower Permian (Upper Pennsylvanian–Asselian) Tobra Formation is exposed in the Salt and Trans Indus ranges of Pakistan. The formation exhibits an alluvial plain (alluvial fan–piedmont alluvial plain) fades association in the Salt Range and Khisor Range. In addition, a stream flow facies association is restricted to the eastern Salt Range. The alluvial plain facies association is comprised of clast‐supported massive conglomerate (Gmc), diamictite (Dm) facies, and massive sandstone (Sm) lithofacies whereas the stream flow‐dominated alluvial plain facies association includes fine‐grained sandstone and siltstone (Fss), fining upwards pebbly sandstone (Sf), and massive mudstone (Fm) lithofacies. The lack of glacial signatures (particularly glacial grooves and striations) in the deposits in the Tobra Formation, which are, in contrast, present in their time‐equivalent and palaeogeographically nearby strata of the Arabian peninsula, e.g. the Al Khlata Formation of Oman and Unayzah B member of the Saudi Arabia, suggests a pro‐ to periglacial, i.e. glaciofluvial depositional setting for the Tobra Formation. The sedimentology of the Tobra Formation attests that the Salt Range, Pakistan, occupied a palaeogeographic position just beyond the maximum glacial extent during Upper Pennsylvanian–Asselian time. |
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Keywords: | Pennsylvanian–Asselian Tobra Formation Salt Range Khisor Range glaciofluvial Pakistan |
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