NSF Award
2111939
The Mongolian Altai are an approximately 2000 km-long mountain range in western Mongolia that are part of a vast mountainous region in central Asia referred to as the Central Asian Orogenic Belt. Understanding how a mountain system that is located >1000 km from a modern tectonic plate boundary originally formed is important as the Altai play an important role in regulating Asian climate and biodiversity and in controlling the distribution and reorganization of Earth materials through erosion and sediment transport. This study will test how the Earth’s crust deforms into mountains in the middle of tectonic plates rather than at the edges. The PIs will use thermochronology (the study of mineral cooling histories) to measure the timing of mountain development and conduct field-based studies of sedimentary rocks to study changes in erosion and deposition patterns caused by mountain uplift. These results will be compared to numerical models testing different ways to form mountains in the middle of tectonic plates. This research will provide important societal outcomes by 1) supporting the training of graduate and undergraduate students in STEM fields including minority and underrepresented students at a Hispanic Serving Institution, 2) increasing participation of women in STEM as both Principal Investigators and graduate students within this project, 3) increasing public scientific literacy through undergraduate education and education outreach, 4) developing partnerships between American and Mongolian scientists, and 5) the development of online interactive field tours for undergraduate education. <br/><br/>Recent large-scale, interdisciplinary projects have led to major advances in our understanding of the rates, relative timing, and periodicity of tectonic plate margin processes that define orographic landscapes. However, our understanding of plate interior orogenesis is less evolved, as intracontinental orogens defy models of orogenesis as a plate-boundary driven process. The Mongolian Altai are part of one of the largest intracontinental orogenic systems–the Central Asian Orogenic Belt, and yet limited data exist to explain the origin of this mountain system. This project will test specific models of intracontinental orogenesis in the Mongolia Altai, each of which predict a different timing, rate, and style of uplift. This research will integrate bedrock and detrital thermochronology, sedimentology and basin analysis, and geomechanical modeling to document the timing of onset of intracontinental orogenesis in the Mongolian Altai; understand fundamental (rheological, geodynamic, inherited) controls on the formation of an orographic landscape in this region; and to understand the possible conditions that produce intracontinental deformation from plate boundary forces and the timescales on which this deformation occurs. These outcomes will allow testing of whether the Mongolian Altai are relict topography from a Mesozoic suture zone, are a geodynamic feature of isostatic or dynamic processes, or formed due to localized deformation from Cenozoic plate boundary stresses. Field and analytical data will provide direct observations to test these hypotheses that can be further constrained by numerical models that interrogate the geomechanical plausibility of these processes. This study will not only provide the first basement thermochronologic dataset from a ~800 km along strike zone within the Mongolian Altai and the first detrital thermochronologic dataset from the entire Altai system (2000 km strike length), but will integrate this dataset with work in contemporaneous sedimentary basins and geomechanical modeling to put these data in a well-constrained geologic context. The proposed research will also improve our understanding of what processes drive formation of intracontinental orogens globally, a major outstanding question in the field of tectonics.<br/><br/>This project is jointly funded by the Tectonics program in the division of Earth Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
