Strain rate analysis of the Kyrgyz Tien Shan from GPS and paleomagnetic data

• Applicant: Professor Dr. Valerian Bachtadse
• Subject Area: Geophysics
• Term: from 2011 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 207156275

• Final Report Year: 2015

Final Report Abstract

The recent and the present day deformations of the Tian Shan continue to be rather complex. Based on a small set of Cenozoic paleomagnetic data and a GPS velocity field consisting of around 700 data points does not unambiguously allow to define rigid blocks. This situation is further complicated by the fact that deformation rates have not been constant even through the late Cenozoic. This is exemplified by the TFF, which has evidently been active in the Holocene (with probable slip rates of up to 10 mm/yr), but does not show any sign of active deformation in the GPS data. Interesting, however, is the great variability in amount and direction of paleomagnetically defined rotations since the Paleocene-Eocene. We might speculate that when approaching the TFF the amount of rotation dramatically increases, and that with increasing distance to these faults the rotation amount decreases continuously. These are concepts, which have already been described using paleomagnetic data, but given the continuous deformation pattern in the region, much more data is needed to better evaluate this assumption. However, considering the currentness of the continuous vs. block tectonic deformation debate AND taken into account the excellent outcrop situation in the western Tian Shan the PI is currently considering a much larger paleomagnetically oriented proposal.

Publications

• 2013, Rigid Block Model versus Continuous Deformation within Continents - GPS and paleomagnetic data from Kyrgyzstan, central Asia, Living on a Magnetic Planet, IAGA, 12th Scientific Assembly, Abstract Volume, 135-136
  Kirscher,U.. Kirscher, U., Zubovich, A., Mikolaichuk, A., Malservisi, R., Hackl, M., Bachtadse, V.
  
• 2013, Velocity covariance in the presence of anisotropic time correlated noise and transient events in GPS time series, Journal of Geodynamics 12/2013
  Hackl,M, Malservisi, R.,Hugentobler, U., Jiang,Y.
  (See online at https://doi.org/10.1016/j.jog.2013.08.007)