Magnitude of post-Middle Jurassic (Bajocian) displacement on the central Altyn Tagh fault system, Northwest China

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doi: 10.1130/0016-7606(2000)112<61:MOPJBD>2.0.CO;2
Authors:Ritts, Bradley D.; Biffi, Ulderico
Author Affiliations:Primary:
Stanford University, Department of Geological and Environmental Sciences, Stanford, CA, United States
AGIP, San Donato Milanese, Italy
Volume Title:Geological Society of America Bulletin
Source:Geological Society of America Bulletin, 112(1), p.61-74. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7606
Publication Date:2000
Note:In English. 47 refs.; illus., incl. sects., strat. cols., 1 table, sketch maps
Summary:The Altyn Tagh fault system, a key structural feature in the tectonic collage of central Asia, is an active left-lateral strike-slip fault system. However, its age of initiation, kinematic history, and total magnitude of displacement are not well known. Middle Jurassic nonmarine sedimentary rocks that crop out along the central segment of the Altyn Tagh fault were deposited in a contiguous Tarim-Qaidam foreland-style basin that was geodynamically linked to Mesozoic contraction in the Tian Shan, Bei Shan, Qilian Shan, and Kunlun Shan. This study documents the best evidence of a piercing point to date, consisting of an offset lacustrine shoreline demarcated by Aalenian-Bajocian open lacustrine strata to the west and fluvial and alluvial strata of comparable age to the east. Detrital compositions, palynology, paleocurrents, and lithostratigraphy support correlation of these sections. Restoration of this Jurassic facies boundary indicates 400±60 km of post-Bajocian left-lateral separation on the Altyn Tagh fault. Consistent with this result, restoration of the Jurassic shoreline aligns felsic plutons across the western segment of the Altyn Tagh fault system that may have been left-laterally offset by 360 km. These two pairs of offset features suggest that the current best estimate for net magnitude of post-Bajocian left-lateral separation on the Altyn Tagh fault is about 360 km. [W.E.S.]
Subsections:Sedimentary petrology
Subjects:Bajocian; Basin analysis; Contraction; Correlation; Displacements; Faults; Fluvial environment; Jurassic; Kinematics; Lateral faults; Left-lateral faults; Lithofacies; Mesozoic; Middle Jurassic; Outcrops; Paleocurrents; Reconstruction; Strike-slip faults; Asia; China; Far East; Kunlun Mountains; Qaidam Basin; Qilian Mountains; Qinghai China; Tarim Basin; Tien Shan; Xinjiang China; Altyn Tagh fault system; Bei Shan; Northwestern China
Abstract Numbers:01M/4658
Record ID:2000016405
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
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