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Lithologic Correlations Across the Eastern North Pamir Suggest a Regionally Extensive Thrust Nappe

Daniel B. Imrecke1, A. C. Robinson1, T. J. Lapen1, C. Jie2, W. Li2, X. Yang2, and Z. Yuan2
1Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77204, USA
2Laboratory of Neotectonics and Geochronology, State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing, 100029, China

Previously unrecognized similarities in lithologies and structural relationships suggest a broad continuity in the tectonic architecture across the region. We compare two regional areas bound by major structural features: 1) the Baoziya and Tanymas thrusts are exposed north and northwest of the Muztaghata massif. The Baoziya/Tanymas thrust hanging-wall consists of upper greenschist to amphibolite facies schists and quartzites with abundant Triassic igneous intrusions. Detrital zircon analyses of the hanging wall yield Permo- Triassic maximum depositional ages. The footwall of the Baoziya Thrust consists of greenschist facies marbles, phyllites, and quartzites with Triassic maximum depositional ages, whereas the Tanymas thrust footwall consists of early Paleozoic sandstones, limestones, and marls. 2) The Torbashi Thrust is exposed south of the Muztaghata massif as a folded klippe. Its hanging wall consists of amphibolite facies schists and gneisses with abundant igneous intrusions. Like the Baoziya/Tanymas hanging-wall, the Torbashi Thrust hanging-wall yields Permo-Triassic maximum depositional ages. The northern exposure of the footwall consists of greenschist facies marbles, quartzites, phyllites, and metavolcanics with Triassic metamorphic age signatures, whereas the southern exposure consists of early Paleozoic strata. Based on structural juxtaposition and lithologic similarities we correlate the north exposure of the Torbashi Thrust with the Boaziya Thrust, and correlate the southwest exposure of the Torbashi thrust with the Tanymas thrust. We propose the Torbashi and Baoziya/Tanymas faults were a continuous structure which formed a regionally extensive thrust nappe in the Northern Pamir.

AAPG Search and Discovery Article #90182©2013 AAPG/SEG Student Expo, Houston, Texas, September 16-17, 2013