Stress field evolution in the northwest Himalayan syntaxis, northern Pakistan

Arnaud Pecher (1) , L. Seeber (2) , Stephane Guillot (1) , François Jouanne (1) , A. Kausar (3) , M. Latif (3) , M. Majid (3) , Gweltaz Mahéo (4) , Jean-Louis Mugnier (1) , Yan Rolland (5) , Peter van Der Beek (1) , Jeremie van Melle (1)

1 LGCA - Laboratoire de Géodynamique des Chaines Alpines
2 LDEO - Lamont-Doherty Earth Observatory
3 Geological Survey of Pakistan
4 LST - Laboratoire de Sciences de la Terre
5 GEOAZUR 6526 - Géoazur

We have conducted a systematic inversion of striated fault planes throughout northern Pakistan in order to better depict the temporal and spatial variations in stress patterns. Two domains are evidenced at a regional scale, separated by the active Raikhot fault, the western boundary of the Nanga Parbat spur. West of this fault, a wrench-type stress field with σ1 axis oriented around N–S predominates in the Karakorum and in Kohistan. It predates Pliocene-Quaternary exhumation of Nanga Parbat and corresponds to the Miocene or earlier regional stress field related to Indian-Asian convergence. East of the Raikhot fault, compression parallel to the belt accounts for initiation of the Nanga Parbat anticlinorium after 5 Ma. It is followed by predominant post-2 Ma extension, both parallel to the belt and NNE–SSW oriented. Thus, in the N–W Himalayan syntaxis, multidirectional extension is juxtaposed on short timescales to shortening either parallel or perpendicular to the belt. Such juxtaposition could be characteristic of strain and stress partitioning during oblique convergence.

Domains: Sciences of the Universe [physics]; Earth Sciences

Arnaud Pecher, L. Seeber, Stephane Guillot, François Jouanne, A. Kausar, et al.. Stress field evolution in the northwest Himalayan syntaxis, northern Pakistan. Tectonics, 2008, 27, pp.TC6005. ⟨10.1029/2007TC002252⟩. ⟨insu-00353754⟩