@article{GhaniSobelZeilingeretal.2020, author = {Ghani, Humaad and Sobel, Edward and Zeilinger, Gerold and Glodny, Johannes and Zapata, Sebastian and Irum, Irum}, title = {Palaeozoic and Pliocene tectonic evolution of the Salt Range constrained by low-temperature thermochronology}, series = {Terra nova}, volume = {33}, journal = {Terra nova}, number = {3}, publisher = {Wiley}, address = {Hoboken}, issn = {0954-4879}, doi = {10.1111/ter.12515}, pages = {293 -- 305}, year = {2020}, abstract = {The Salt Range in Pakistan exposes Precambrian to Pleistocene strata outcropping along the Salt Range Thrust (SRT). To better understand the in-situ Cambrian and Pliocene tectonic evolution of the Pakistan Subhimalaya, we have conducted low-temperature thermochronological analysis using apatite (U-Th-Sm)/He and fission track dating. We combine cooling ages from different samples located along the thrust front of the SRT into a thermal model that shows two major cooling events associated with rifting and regional erosion in the Late Palaeozoic and SRT activity since the Pliocene. Our results suggest that the SRT maintained a long-term average shortening rate of similar to 5-6 mm/yr and a high exhumation rate above the SRT ramp since similar to 4 Ma.}, language = {en} } @article{BehyariMohajjelSobeletal.2017, author = {Behyari, Mahdi and Mohajjel, Mohammad and Sobel, Edward and Rezaeian, Mahnaz and Moayyed, Mohssen and Schmidt, Alexander}, title = {Analysis of exhumation history in Misho Mountains, NW Iran}, series = {Neues Jahrbuch f{\"u}r Geologie und Pal{\"a}ontologie : merged with Neues Jahrbuch f{\"u}r Geol. und Pal{\"a}ont. Monatshefte". Abhandlungen}, volume = {283}, journal = {Neues Jahrbuch f{\"u}r Geologie und Pal{\"a}ontologie : merged with Neues Jahrbuch f{\"u}r Geol. und Pal{\"a}ont. Monatshefte". Abhandlungen}, number = {3}, publisher = {Schweizerbart}, address = {Stuttgart}, issn = {0077-7749}, doi = {10.1127/njgpa/2017/0642}, pages = {291 -- 308}, year = {2017}, abstract = {The Misho complex in Northwest Iran is a prominent topographic massif bounded by well known active faults. Our new structural analysis of this area indicates that faulting has important role in the exhumation of this complex. The conjugate orientation of the North and South Misho Faults caused uplift in the Misho and exhumation of the Precambrian crystalline basement. Our structural and stratigraphic data shows that rapid uplift could have been initiation since the 21-22 Ma and exhumation rate was about 0.16 to 0.24 km/Ma. To refine this age, we performed U/Pb analysis of detrital zircon from the Upper Red Formation using LA-ICP-MS. We conducted AFT analysis on 6 basement samples from the hanging wall and 1 sample from the Upper Red Formation in the footwall NMF. Uplift in the hanging wall of NMF led to resting of sample 916 marl. This geochronologic and thermochronologic data shows that exhumation in the MC is diachronously along strike and affected by faults. The phase of exhumation is documented in the study area and entire Iranian plateau is related to the final closure of the Neo-Tethys and northward motion of the Arabian Plate.}, language = {en} } @article{EugsterThiedeScherleretal.2018, author = {Eugster, Patricia and Thiede, Rasmus Christoph and Scherler, Dirk and St{\"u}bner, Konstanze and Sobel, Edward and Strecker, Manfred}, title = {Segmentation of the Main Himalayan Thrust Revealed by Low-Temperature Thermochronometry in the Western Indian Himalaya}, series = {Tectonics}, volume = {37}, journal = {Tectonics}, number = {8}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0278-7407}, doi = {10.1029/2017TC004752}, pages = {2710 -- 2726}, year = {2018}, abstract = {Despite remarkable tectonostratigraphic similarities along the Himalayan arc, pronounced topographic and exhumational variability exists in different morphotectonic segments. The processes responsible for this segmentation are debated. Of particular interest is a 30- to 40-km-wide orogen-parallel belt of rapid exhumation that extends from central Nepal to the western Himalaya and its possible linkage to a midcrustal ramp in the basal decollement, and the related growth of Lesser Himalayan duplex structures. Here we present 26 new apatite fission track cooling ages from the Beas-Lahul region, at the transition from the Central to the Western Himalaya (77 degrees-78 degrees E) to investigate segmentation in the Himalayan arc from a thermochronologic perspective. Together with previously published data from this part of the orogen, we document significant lateral changes in exhumation between the Dhauladar Range to the west, the Beas-Lahul region, and the Sutlej area to the east of the study area. In contrast to the Himalayan front farther east, exhumation in the far western sectors is focused at the frontal parts of the mountain range and associated with the hanging wall of the Main Boundary Thrust fault ramp. Our results allow us to spatially correlate the termination of the rapid exhumation belt with a midcrustal ramp to the west. We suggest that a plunging anticline at the northwestern edge of the Larji-Kullu-Rampur window represents the termination of the Central Himalayan segment, which is related to the evolution of the Lesser Himalayan duplex. Key Points}, language = {en} } @article{DeekenThiedeSobeletal.2011, author = {Deeken, Anke and Thiede, Rasmus Christoph and Sobel, Edward and Hourigan, J. K. and Strecker, Manfred}, title = {Exhumational variability within the Himalaya of northwest India}, series = {Earth \& planetary science letters}, volume = {305}, journal = {Earth \& planetary science letters}, number = {1-2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2011.02.045}, pages = {103 -- 114}, year = {2011}, abstract = {In the Himalaya of Chamba, NW India, a major orographic barrier in front of the Greater Himalayan Range extracts a high proportion of the monsoonal rainfall along its southern slopes and effectively shields the orogen interior from moisture-bearing winds. Along a similar to 100-km-long orogen perpendicular transect, 28 new apatite fission track (AFT) and 30 new zircon (U-Th)/He (ZHe) cooling ages reveal marked variations in age distributions and long-term exhumation rates between the humid frontal range and the semi-arid orogen interior. On the southern topographic front, very young, elevation-invariant AFT ages of <4 Ma have been obtained that are concentrated in a similar to 30-km-wide zone; 1-D-thermal modeling suggests a Plio-Pleistocene mean erosion rate of 0.8-1.9 mm yr(-1). In contrast, AFT and ZHe ages within the orogen interior are older (4-9 and 7-18 Ma, respectively), are positively correlated with sample elevation, and yield lower mean erosion rates (0.3-0.9 mm yr(-1)). Protracted low exhumation rates within the orogen interior over the last similar to 15 Myr prevailed contemporaneously with overall humid conditions and an effective erosional regime within the southern Himalaya. This suggests that the frontal Dhauladar Range was sufficiently high during this time to form an orographic barrier, focusing climatically enhanced erosional processes and tectonic deformation there. Thrusting along the two frontal range-bounding thrust, the Main Central Thrust and the Main Boundary Thrusts, was initiated at least similar to 15 Ma ago and has remained localized since then. The lack of evidence for localized uplift farther north indicates either a rather flat decollement with no ramp or the absence of active duplex systems beneath the interior of Chamba. Exhumational variability within Chamba is best explained as the result of continuous thrusting along a major basal decollement, with a flat beneath the slowly exhuming internal compartments and a steep frontal ramp at the rapidly exhuming frontal range. The pattern in Chamba contrasts with what is observed elsewhere along the Himalaya, where exhumation is focused in a zone similar to 150 km north of the orogenic front. In the NW Himalaya, preserved High Himalayan Crystalline nappes and Lesser Himalayan windows alternate on a relatively small scale of <100 km; these alternations are closely correlated with the pattern of exhumation. Although the spatial distribution of high-exhumation zones varies considerably between individual Himalayan sectors, all of these zones are closely correlated with locally higher rock-uplift rates, sharp topographic discontinuities, and focused orographic precipitation, suggesting strong feedbacks between tectonically driven rock uplift, orographically enhanced precipitation, and erosional processes.}, language = {en} } @article{SobelChenSchoenbohmetal.2013, author = {Sobel, Edward and Chen, Jie and Schoenbohm, Lindsay M. and Thiede, Rasmus Christoph and Stockli, Daniel F. and Sudo, Masafumi and Strecker, Manfred}, title = {Oceanic-style subduction controls late Cenozoic deformation of the Northern Pamir orogen}, series = {Earth \& planetary science letters}, volume = {363}, journal = {Earth \& planetary science letters}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2012.12.009}, pages = {204 -- 218}, year = {2013}, abstract = {The northern part of the Pamir orogen is the preeminent example of an active intracontinental subduction zone in the early stages of continent-continent collision. Such zones are the least understood type of plate boundaries because modern examples are few and of limited access, and ancient analogs have been extensively overprinted by subsequent tectonic and erosion processes. In the Pamir, it has been assumed that most of the plate convergence was accommodated by overthrusting along the plate-bounding Main Pamir Thrust (MPT), which forms the principal northern mountain and deformation front of the Pamir. However, the synopsis of our new and previously published thermochronologic data from this region shows that the hanging wall of the MPT experienced relatively minor amounts of late Cenozoic exhumation. The Pamir orogen as a whole is an integral part of the overriding plate in a subduction system, while the remnant basin to the north constitutes the downgoing plate, with the bulk of the convergence accommodated by underthrusting. Herein, we demonstrate that the observed deformation of the upper and lower plates within the Pamir-Alai convergence zone resembles highly arcuate oceanic subduction systems characterized by slab rollback, subduction erosion, subduction accretion, and marginal slab-tear faults. We suggest that the curvature of the North Pamir is genetically linked to the short width and rollback of the south-dipping Alai slab; northward motion (indentation) of the Pamir is accommodated by crustal processes related to this rollback. The onset of south-dipping subduction is tentatively linked to intense Pamir contraction following break-off of the north-dipping Indian slab beneath the Karakoram.}, language = {en} } @article{ThiedeEhlers2013, author = {Thiede, Rasmus Christoph and Ehlers, Todd}, title = {Large spatial and temporal variations in Himalayan denudation}, series = {Earth \& planetary science letters}, volume = {371}, journal = {Earth \& planetary science letters}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2013.03.004}, pages = {278 -- 293}, year = {2013}, abstract = {In the last decade growing interest has emerged in quantifying the spatial and temporal variations in mountain building. Until recently, insufficient data have been available to attempt such a task at the scale of large orogens such as the Himalaya. The Himalaya accommodates ongoing convergence between India and Eurasia and is a focal point for studying orogen evolution and hypothesized interactions between tectonics and climate. Here we integrate 1126 published bedrock mineral cooling ages with a transient 1D Monte-Carlo thermal-kinematic erosion model to quantify the denudation histories along similar to 2700 km of the Himalaya. The model free parameter is a temporally variable denudation rate from 50 Ma to present. Thermophysical material properties and boundary conditions were tuned to individual study areas. Monte-Carlo simulations were conducted to identify the range of denudation histories that can reproduce the observed cooling ages. Results indicate large temporal and spatial variations in denudation and these are resolvable across different tectonic units of the Himalaya. More specifically, across > 1000 km of the southern Greater Himalaya denudation rates were highest (similar to 1.5-3 mm/yr) between similar to 10 and 2 Ma and lower (0.5-2.6 mm/yr) over the last 2 My. These differences are best determined in the NW-Himalaya. In contrast to this, across the similar to 2500 km length of the northern Greater Himalaya denudation rates vary over length scales of similar to 300-1700 km. Slower denudation (<1 mm/yr) occurred between 10 and 4 Ma followed by a large increase (1.2-2.6 mm/yr) in the last similar to 4 Ma. We find that only the southern Greater Himalayan Sequence clearly supports a continuous co-evolution of tectonics, climate and denudation. Results from the higher elevation northern Greater Himalaya suggest either tectonic driven variations in denudation due to a ramp-flat geometry in the main decollement and/or recent glacially enhanced denudation.}, language = {en} } @article{ThiedeSobelChenetal.2013, author = {Thiede, Rasmus Christoph and Sobel, Edward and Chen, Jie and Schoenbohm, Lindsay M. and Stockli, Daniel F. and Sudo, Masafumi and Strecker, Manfred}, title = {Late Cenozoic extension and crustal doming in the India-Eurasia collision zone new thermochronologic constraints from the NE Chinese Pamir}, series = {Tectonics}, volume = {32}, journal = {Tectonics}, number = {3}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0278-7407}, doi = {10.1002/tect.20050}, pages = {763 -- 779}, year = {2013}, abstract = {The northward motion of the Pamir indenter with respect to Eurasia has resulted in coeval thrusting, strike-slip faulting, and normal faulting. The eastern Pamir is currently deformed by east-west oriented extension, accompanied by uplift and exhumation of the Kongur Shan (7719m) and Muztagh Ata (7546m) gneiss domes. Both domes are an integral part of the footwall of the Kongur Shan extensional fault system (KES), a 250 km long, north-south oriented graben. Why active normal faulting within the Pamir is primarily localized along the KES and not distributed more widely throughout the orogen has remained unclear. In addition, relatively little is known about how deformation has evolved throughout the Cenozoic, despite refined estimates on present-day crustal deformation rates and microseismicity, which indicate where crustal deformation is presently being accommodated. To better constrain the spatiotemporal evolution of faulting along the KES, we present 39 new apatite fission track, zircon U-Th-Sm/He, and Ar-40/Ar-39 cooling ages from a series of footwall transects along the KES graben shoulder. Combining these data with present-day topographic relief, 1-D thermokinematic and exhumational modeling documents successive stages, rather than synchronous deformation and gneiss dome exhumation. While the exhumation of the Kongur Shan commenced during the late Miocene, extensional processes in the Muztagh Ata massif began earlier and have slowed down since the late Miocene. We present a new model of synorogenic extension suggesting that thermal and density effects associated with a lithospheric tear fault along the eastern margin of the subducting Alai slab localize extensional upper plate deformation along the KES and decouple crustal motion between the central/western Pamir and eastern Pamir/Tarim basin.}, language = {en} }