TY  - JOUR
A1  - Thiede, Rasmus Christoph
A1  - Arrowsmith, J. Ramón
A1  - Bookhagen, Bodo
A1  - McWilliams, Michael O.
A1  - Sobel, Edward
A1  - Strecker, Manfred
T1  - Dome formation and extension in the Tethyan Himalaya, Leo Pargil, northwest India
N2  - Metamorphic dome complexes occur within the internal structures of the northern Himalaya and southern Tibet. Their origin, deformation, and fault displacement patterns are poorly constrained. We report new field mapping, structural data, and cooling ages from the western flank of the Leo Pargil dome in the northwestern Himalaya in an attempt to characterize its post-middle Miocene structural development. The western flank of the dome is characterized by shallow, west-dipping pervasive foliation and WNW-ESE mineral lineation. Shear-sense indicators demonstrate that it is affected by east-west normal faulting that facilitated exhumation of high-grade metamorphic rocks in a contractional setting. Sustained top-to-northwest normal faulting during exhumation is observed in a progressive transition from ductile to brittle deformation. Garnet and kyanite indicate that the Leo Pargil dome was exhumed from the mid-crust. Ar- 40/Ar-39 mica and apatite fission track (AFT) ages constrain cooling and exhumation pathways front 350 to 60 degrees C and suggest that the dome cooled in three stages since the middle Miocene. Ar-40/Ar-39 white mica ages of 16-14 Ma suggest a first phase of rapid cooling and provide minimum estimates for the onset of dome exhumation. AFT ages between 10 and 8 Ma suggest that ductile fault displacement had ceased by then, and AFT track-length data from high-elevation samples indicate that the rate of cooling had decreased significantly. We interpret this to indicate decreased fault displacement along the Leo Pargil shear zone and possibly a transition to the Kaurik-Chango normal fault system between 10 and 6 Ma. AFT ages from lower elevations indicate accelerated cooling since the Pliocene that cannot be related to pure fault displacement, and therefore may reflect more pronounced regionally distributed and erosion-driven exhumation
Y1  - 2006
U6  - https://doi.org/10.1130/B25872.1
ER  - 
TY  - JOUR
A1  - Thiede, Rasmus Christoph
A1  - Arrowsmith, J. Ramón
A1  - Bookhagen, Bodo
A1  - McWilliams, Michael O.
A1  - Sobel, Edward
A1  - Strecker, Manfred
T1  - From tectonically to erosionally controlled development of the Himalayan orogen
N2  - Whether variations in the spatial distribution of erosion influence the location, style, and magnitude of deformation within the Himalayan orogen is a matter of debate. We report new Ar-40/Ar-39 white mica and apatite fission- track (AFT) ages that measure the vertical component of exhumation rates along an similar to 120-km-wide NE-SW transect spanning the greater Sutlej region of northwest India. The Ar-40/Ar-39 data indicate that first the High Himalayan Crystalline units cooled below their closing temperature during the early to middle Miocene. Subsequently, Lesser Himalayan Crystalline nappes cooled rapidly, indicating southward propagation of the orogen during late Miocene to Pliocene time. The AFT data, in contrast, imply synchronous exhumation of a NE-SW-oriented similar to 80 x 40 km region spanning both crystalline nappes during the Pliocene-Quaternary. The locus of pronounced exhumation defined by the AFT data correlates with a region of high precipitation, discharge, and sediment flux rates during the Holocene. This correlation suggests that although tectonic processes exerted the dominant control on the denudation pattern before and until the middle Miocene; erosion may have been the most important factor since the Pliocene
Y1  - 2005
SN  - 0091-7613
ER  - 
TY  - JOUR
A1  - Hermanns, Reginald L.
A1  - Trauth, Martin H.
A1  - McWilliams, Michael O.
A1  - Strecker, Manfred
T1  - Tephrochronologic Constraints on temporal Distribution of large Landslides in NW-Argentina
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Blisniuk, Peter Michael
A1  - Hacker, Bradley R.
A1  - Glodny, Johannes
A1  - Ratschbacher, Lothar
A1  - Bi, Siwen
A1  - Wu, Zhenhan
A1  - McWilliams, Michael O.
A1  - Calvert, Andy
T1  - Normal faulting in central Tibet since at least 13.5 Myr
Y1  - 2001
ER  -