@article{bayasgalan_wegmann_bayasgalan_2022, title={Contrasting late Miocene to present weathering regimes across the Khangay Mountains, Mongolia}, volume={8}, ISSN={2590-0560}, url={http://dx.doi.org/10.1016/j.jaesx.2022.100113}, DOI={10.1016/j.jaesx.2022.100113}, abstractNote={Our understanding of climate change impacts on the geomorphology of terrestrial landscapes is often derived from proxy sedimentary records preserved in depositional fluvial and lacustrine basins that integrate landscape responses. At million-year time scales, most mountainous regions are characterized by net erosion and the export of chemically and physically weathered bedrock. For example, in the Khangay Mountains of central Mongolia, late Cenozoic valley-conforming lava flows preserve “snapshots” of hillslope weathering regimes in the headwaters of the Selenga-Baikal depositional system during the consequential climate transition from the late Miocene (ca. 12 Ma) into the Quaternary. This research aims to characterize the relative importance of chemical and physical weathering to landscape development in this upland intracontinental setting through an investigation of geochemical major and minor trace elemental composition of well-developed paleosols formed in metasediments (middle Orkhon), granite (upper Orkhon), and Miocene fluvial deposits (upper Chuluut) preserved beneath basaltic lavas at 11.9, 7.5 and 3.1 Ma, respectively. We used the Chemical Index of alteration (CIA), Plagioclase Index of Alteration (PIA), and Chemical Index of Weathering (CIW) to derive an integrated paleoclimate regime from the three lava flow-buried paleosol locations. Results reveal that from the late Miocene into the Pliocene, the climate was warmer and slightly more humid than today in the upland continental interior of west-central Mongolia. This result matches the long-term paleo records from Lake Baikal and late Cenozoic global cooling trends from other proxies.}, journal={Journal of Asian Earth Sciences: X}, publisher={Elsevier BV}, author={Bayasgalan, Gantulga and Wegmann, Karl W. and Bayasgalan, Amgalan}, year={2022}, month={Dec}, pages={100113} }
 @article{gregory_mac niocaill_walker_bayasgalan_craig_2018, title={Vertical axis rotation (or lack thereof) of the eastern Mongolian Altay Mountains: Implications for far-field transpressional mountain building}, volume={736}, ISSN={["1879-3266"]}, DOI={10.1016/j.tecto.2018.03.020}, abstractNote={The Altay Mountains of Western Mongolia accommodate 10–20% of the current shortening of the India-Asia collision in a transpressive regime. Kinematic models of the Altay require faults to rotate anticlockwise about a vertical axis in order to accommodate compressional deformation on the major strike slip faults that cross the region. Such rotations should be detectable by palaeomagnetic data. Previous estimates from the one existing palaeomagnetic study from the Altay, on Oligocene and younger sediments from the Chuya Basin in the Siberian Altay, indicate that at least some parts of the Altay have experienced up to 39 ± 8° of anticlockwise rotation. Here, we present new palaeomagnetic results from samples collected in Cretaceous and younger sediments in the Zereg Basin along the Har-Us-Nuur fault in the eastern Altay Mountains, Mongolia. Our new palaeomagnetic results from the Zereg Basin provide reliable declinations, with palaeomagnetic directions from 10 sites that pass a fold test and include magnetic reversals. The declinations are not significantly rotated with respect to the directions expected from Cretaceous and younger virtual geomagnetic poles, suggesting that faults in the eastern Altay have not experienced a large degree of vertical axis rotation and cannot have rotated >7° in the past 5 m.y. The lack of rotation along the Har-Us-Nuur fault combined with a large amount of rotation in the northern Altay fits with a kinematic model for transpressional deformation in which faults in the Altay have rotated to an orientation that favours the development of flower structures and building of mountainous topography, while at the same time the range widens at the edges as strain is transferred to better oriented structures. Thus the Har-Us-Nuur fault is a relatively young fault in the Altay, and has not yet accommodated significant rotation.}, journal={TECTONOPHYSICS}, author={Gregory, Laura C. and Mac Niocaill, Conall and Walker, Richard T. and Bayasgalan, Gantulga and Craig, Tim J.}, year={2018}, month={Jun}, pages={31–46} }