Neogene uplift of the Tian Shan Mountains observed in the magnetic record of the Jingou River section (northwest China)
Article first published online: 31 MAR 2009
Copyright 2009 by the American Geophysical Union.
Volume 28, Issue 2, April 2009
How to Cite
2009), Neogene uplift of the Tian Shan Mountains observed in the magnetic record of the Jingou River section (northwest China), Tectonics, 28, TC2008, doi:10.1029/2007TC002137., et al. (
- Issue published online: 31 MAR 2009
- Article first published online: 31 MAR 2009
- Manuscript Accepted: 15 DEC 2008
- Manuscript Revised: 25 JUN 2008
- Manuscript Received: 27 MAR 2008
- Tian Shan;
 The Tian Shan Mountains constitute central Asia's longest and highest mountain range. Understanding their Cenozoic uplift history thus bears on mountain building processes in general, and on how deformation has occurred under the influence of the India-Asia collision in particular. In order to help decipher the uplift history of the Tian Shan, we collected 970 samples for magnetostratigraphic analysis along a 4571-m-thick section at the Jingou River (Xinjiang Province, China). Stepwise alternating field and thermal demagnetization isolate a linear magnetization component that is interpreted as primary. From this component, a magnetostratigraphic column composed of 67 polarity chrons are correlated with the reference geomagnetic polarity timescale between ∼1 Ma and ∼23.6 Ma, with some uncertainty below ∼21 Ma. This correlation places precise temporal control on the Neogene stratigraphy of the southern Junggar Basin and provides evidence for two significant stepwise increases in sediment accumulation rate at ∼16–15 Ma and ∼11–10 Ma. Rock magnetic parameters also undergo important changes at ∼16–15 Ma and ∼11–10 Ma that correlate with changes in sedimentary depositional environments. Together with previous work, we conclude that growth history of the modern Tian Shan Mountains includes two pulses of uplift and erosion at ∼16–15 Ma and ∼11–10 Ma. Middle to upper Tertiary rocks around the Tian Shan record very young (<∼5 Ma) counterclockwise paleomagnetic rotations, on the order of 15° to 20°, which are interpreted as because of strain partitioning with a component of sinistral shear that localized rotations in the piedmont.