Partitioning of India‐Eurasia convergence in the Pamir‐Hindu Kush from GPS measurements

Abstract

Convergence of 29 ± 1 mm/yr between the NW corner of the Indian plate and Asia is accommodated by a combination of thrust and strike‐slip faulting on prominent faults and apparent distributed deformation within the Hindu Kush, Pamir, South Tien Shan and Kohistan Ranges. An upper bound to the slip rate of known faults is obtained by ignoring distributed strain and rotation: convergence occurs on thrust faults north of the Peshawar Basin (13 ± 1 mm/yr) and in the Alai‐South Tien Shan (12 ± 2 mm/yr), and shear on the northeast‐trending northern Chaman‐Gardiz‐Konar system (18 ± 1mm/yr) and the Darvaz‐Karakul fault zone (11 ± 2 mm/yr). Slip rates on the Herat and Talas‐Ferghana faults are small (<2 mm/yr). Shortening not attributable to known active faults occurs within the Hindu Kush and central Pamir (16 ± 2 mm/yr) with concomitant east‐west extension in the latter of 9 ± 2 mm/yr. This diversity of strain styles confirms the importance of mechanical heterogeneity to continental tectonics and shows that the Pamir, although less than half the size, behaves more like Tibet than like a linear belt of localized deformation.

Rates of river incision across the main tectonic units of the Pamir identified using optically stimulated luminescence dating of fluvial terraces

“…1). Late Quaternary lateral motion across the DFZ reaches ∼12 mm/yr (Trifonov, 1978;Mohadjer et al, 2010). The strike-slip faults in the south-eastern Pamir that root in the KFZ display low lateral displacement rates of < 1 mm/yr (Strecker et al, 1995).…”

Present‐day crustal thinning in the southern and northern Tibetan Plateau revealed by GPS measurements

“…The data set of He et al [2013] contains 16 campaign-mode sites located in a localized dense network across central segment of Altyn Tagh Fault from the Tarim Basin to northern Tibet and measured twice in the period of 2009-2011. In addition, we show published velocities for surrounding regions (Figure 1): from the Nepal Himalaya [e.g., Banerjee et al, 2008;Bettinelli et al, 2006;Bilham et al, 1997;Feldl and Bilham, 2006], northwest Himalaya [Banerjee and Bürgmann, 2002], Pamir-Hindu Kush [Ischuk et al, 2013;Mohadjer et al, 2010], Kashmir and Ladakh Himalaya [e.g., Jade et al, 2004;Schiffman et al, 2013], eastern Himalaya, Naga Hills, and Shillong Plateau [Devachandra et al, 2014;Vernant et al, 2014].…”

“…Although coverage is sparse in some parts of Tibet (Figure 1), GPS velocities, however, can be used to infer strain rates across the region, and we exploit them here to make such a comparison. confidence ellipses), including some data from other published sources, e.g., Tien Shan [Zubovich et al, 2010], Pamir and Hindu Kush regions [Ischuk et al, 2013;Mohadjer et al, 2010], Himalaya [Ader et al, 2012;Banerjee and Bürgmann, 2002;Banerjee et al, 2008;Bettinelli et al, 2006;Jouanne et al, 2014;Schiffman et al, 2013], and Myanmar [Devachandra et al, 2014;Gahalaut et al, 2013;Maurin et al, 2010]. The India-Eurasia rotation pole for an India plate reference frame with respect to Eurasia lies at 27.46°N…”

Tectonic and climatic forcing on the Panj river system during the Quaternary

“…The Pamir constitutes the westernmost part of the India-Asia collision zone, one of Earth's largest and most rapidly deforming intra-continental orogens (e.g. Le Pichon et al, 1992;Reigber et al, 2001;Mohadjer et al, 2010). Surface processes in such active orogens involve erosional and depositional mechanisms and their complex feedbacks, controlled by the interplay between tectonic and climatic forcing (e.g.…”