@article{MacaulaySobelMikolaichuketal.2013, author = {Macaulay, Euan A. and Sobel, Edward and Mikolaichuk, Alexander and Landgraf, Angela and Kohn, Barry and Stuart, Finlay}, title = {Thermochronologic insight into late Cenozoic deformation in the basement-cored Terskey Range, Kyrgyz Tien Shan}, series = {Tectonics}, volume = {32}, journal = {Tectonics}, number = {3}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0278-7407}, doi = {10.1002/tect.20040}, pages = {487 -- 500}, year = {2013}, abstract = {Basement-cored ranges formed by reverse faulting within intracontinental mountain belts are often composed of poly-deformed lithologies. Geological data capable of constraining the timing, magnitude, and distribution of the most recent deformational phase are usually missing in such ranges. In this paper, we present new low temperature thermochronological and geological data from a transect through the basement-cored Terskey Range, located in the Kyrgyz Tien Shan. Using these data, we are able to investigate the range's late Cenozoic deformation for the first time. Displacements on reactivated faults are constrained and deformation of thermochronologically derived structural markers is assessed. These structural markers postdate the earlier deformational phases, providing the only record of Cenozoic deformation and of the reactivation of structures within the Terskey Range. Overall, these structural markers have a southern inclination, interpreted to reflect the decreasing inclination of the reverse fault bounding the Terskey Range. Our thermochronological data are also used to investigate spatial and temporal variations in the exhumation of the Terskey Range, identifying a three-stage Cenozoic exhumation history: (1) virtually no exhumation in the Paleogene, (2) increase to slightly higher exhumation rates at similar to 26-20Ma, and (3) significant increase in exhumation starting at similar to 10Ma.}, language = {en} } @article{LoebensSobelBenseetal.2013, author = {Loebens, Stefan and Sobel, Edward and Bense, Frithjof A. and Wemmer, Klaus and Dunkl, Istvan and Siegesmund, Siegfried}, title = {Refined exhumation history of the northern Sierras Pampeanas, Argentina}, series = {Tectonics}, volume = {32}, journal = {Tectonics}, number = {3}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0278-7407}, doi = {10.1002/tect.20038}, pages = {453 -- 472}, year = {2013}, abstract = {The Sierra de Aconquija and Cumbres Calchaquies in the thick-skinned northern Sierras Pampeanas, NW Argentina present an ideal setting to investigate the tectonically and erosionally controlled exhumation and uplift history of mountain ranges using thermochronological methods. Although these ranges are located along strike of one another, their spatiotemporal evolution varies significantly. Integrating modeled cooling histories constrained by K-Ar ages of muscovite and biotite, apatite fission track data as well as (U-Th)/He measurement of zircon and apatite reveal the structural evolution of these ranges beginning in the late stage of the Paleozoic Famatinian Orogeny. Following localized rift-related exhumation in the central part of the study area and slow erosion elsewhere, growth of the modern topography commenced in the Cenozoic during Andean deformation. The main activity occurred during the late Miocene, with varying magnitudes of rock uplift, surface uplift, and exhumation in the two mountain ranges. The Cumbres Calchaquies is characterized by a total of 5-7km of vertical rock uplift, around 3km of crestal surface uplift, and a maximum exhumation of 2-4km since that time. The Sierra de Aconquija experienced 10-13km of vertical rock uplift, similar to 4-5km of peak surface uplift, and 6-8km of exhumation since around 9Ma. Much of this exhumation occurred along a previously poorly recognized fault. Miocene reactivation of Cretaceous rift structures may explain along-strike variations within these ranges. Dating of sedimentary samples from adjacent basins supports the evolutionary model developed for the mountain ranges.}, language = {en} }