Magnetostratigraphic data on Neogene growth folding in the foreland basin of the southern Tianshan Mountains
- 1Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China
- 2Department of Oilfield Exploration and Development, Sinopec, Beijing 100029, China
- *E-mail: jmsun{at}mail.igcas.ac.cn.
Abstract
The Tianshan Range is one of the longest and highest mountain belts in Central Asia, stretching east-west for ~2500 km. Uplift of this late Paleozoic orogenic belt resulted from intracontinental deformation caused by the collision of the Indian and Eurasian plates during the Cenozoic era. To constrain the timing of Cenozoic tectonic deformation of the Tianshan Range, we analyzed the magnetostratigraphy of 3780-m-thick Neogene deposits from the Kuqa foreland basin of southern Tianshan. The geometry measurements and magnetic fabric data show that syntectonic growth strata began to accumulate at ~6.5 Ma ago, indicating that crustal shortening initiated in the latest Miocene. The increase in sedimentation rate and an abrupt change of the magnetic fabric parameters also occurred at 6.5 Ma, accompanied by onset of syntectonic growth strata. The latest Miocene crustal shortening is a significant tectonic event in the foreland basin of the southern Tianshan Range in response to the India-Eurasia collision.
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- Received 30 March 2009.
- Revision received 19 June 2009.
- Accepted 30 June 2009.
- © 2009 Geological Society of America
