Geometry, kinematics, and landscape characteristics of an active transtension zone, Karakoram fault system, Southwest Tibet

We investigate the style of active transtensional deformation and characteristics of the landscape along the southern segment of the Karakoram fault system through field mapping, structural analysis, and examination of digital topography (SRTM, ASTER), multi-spectral (ASTER, Landsat 7+), and panchromatic (Corona photography) imagery. Our data suggests that wrench-dominated transtension is occurring within a 90-km-wide zone; simple shear within the zone is accommodated by right-lateral R and P shears as well as left-lateral R' shears, vertical shortening is accommodated by similar to north-striking extensional shear zones and horizontal shortening is accommodated by similar to east-west-trending transtension-related corrugations. Drainage divides strike at high angles and subparallel to the transtension zone. Those that strike at high angles to the zone can be explained by movement along north-striking extensional fault systems, while the geometry of drainage divides subparallel to the zone are consistent with uplift of corrugations as well as rapid uplift of mountain ranges by normal-right-slip faulting. (C) 2006 Elsevier Ltd. All rights reserved.