@article{GeorgievaGallagherSobczyketal.2019, author = {Georgieva, Viktoria and Gallagher, Kerry and Sobczyk, Artur and Sobel, Edward and Schildgen, Taylor F. and Ehlers, Todd and Strecker, Manfred}, title = {Effects of slab-window, alkaline volcanism, and glaciation on thermochronometer cooling histories, Patagonian Andes}, series = {Earth \& planetary science letters}, volume = {511}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2019.01.030}, pages = {164 -- 176}, year = {2019}, abstract = {Southern Patagonia is a prime example of ongoing oceanic ridge collision and slab-window formation sustained over several million years. The impact of these phenomena on the thermal structure and exhumation of the crust have been mainly assessed with low-temperature thermochronology of bedrock samples. Here, we infer thermal histories from new and existing thermochronological data from the region of most recent ridge collision. In particular, we evaluate the potential far-reaching thermal effects of the evolving slab window, which have previously been considered responsible for patterns of late Miocene reheating associated with back-arc alkaline volcanism. Our model results define protracted cooling since similar to 15 Ma and stepwise exhumation since the late Miocene. The pattern of stepwise exhumation closely matches the onset of Patagonian glaciation at 7 Ma and the successive pulse of glacial incision coeval with neotectonic activity since 3-4 Ma that are also documented by independent geological and geomorphological evidence in the region. Importantly, our findings challenge the recently suggested lack of glacial erosion and incision since 5 Ma in this region. Furthermore, in contrast to previous modelling studies, we find that the available data do not evidence a previously proposed northward-propagating heating event associated with alkaline volcanism. We hypothesize that the anomalous alkaline volcanism in the Patagonian back-arc might be related to trench-orthogonal tears aligned with transform faults in the subducting plate. The substantial differences from the previous modelling procedure on some of the same samples is demonstrated to result from an important lack of convergence in model runs. (C) 2019 Elsevier B.V. All rights reserved.}, 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} }