TY - JOUR A1 - Schildgen, Taylor F. A1 - van der Beek, Peter A. A1 - D'Arcy, Mitch A1 - Roda-Boluda, Duna N. A1 - Orr, Elizabeth N. A1 - Wittmann, Hella T1 - Quantifying drainage-divide migration from orographic rainfall over geologic timescales BT - Sierra de Aconquija, southern Central Andes JF - Earth & planetary science letters N2 - Drainage-divide migration, controlled by rock-uplift and rainfall patterns, may play a major role in the geomorphic evolution of mountain ranges. However, divide-migration rates over geologic timescales have only been estimated by theoretical studies and remain empirically poorly constrained. Geomorphological evidence suggests that the Sierra de Aconquija, on the eastern side of the southern Central Andes, northwest Argentina, is undergoing active westward drainage-divide migration. The mountain range has been subjected to steep rock trajectories and pronounced orographic rainfall for the last several million years, presenting an ideal setting for using low-temperature thermochronometric data to explore its topographic evolution. We perform three-dimensional thermal-kinematic modeling of previously published thermochronometric data spanning the windward and leeward sides of the range to explore the most likely structural and topographic evolution of the range. We find that the data can be explained by scenarios involving drainage-divide migration alone, or by scenarios that also involve changes in the structures that have accommodated deformation through time. By combining new Be-10-derived catchment-average denudation rates with geomorphic constraints on probable fault activity, we conclude that the evolution of the range was likely dominated by west-vergent faulting on a high-angle reverse fault underlying the range, together with westward drainage-divide migration at a rate of several km per million years. Our findings place new constraints on the magnitudes and rates of drainage-divide migration in real landscapes, quantify the effects of orographic rainfall and erosion on the topographic evolution of a mountain range, and highlight the importance of considering drainage-divide migration when interpreting thermochronometer age patterns. KW - drainage-divide migration KW - landscape evolution KW - orographic rainfall KW - thermochronology KW - cosmogenic nuclides KW - Central Andes Y1 - 2022 U6 - https://doi.org/10.1016/j.epsl.2021.117345 SN - 0012-821X SN - 1385-013X VL - 579 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Schildgen, Taylor F. A1 - Hoke, Gregory D. T1 - The topographic evolution of the central andes JF - Elements : an international magazine of mineralogy, geochemistry, and petrology N2 - Changes in topography on Earth, particularly the growth of major mountain belts like the Central Andes, have a fundamental impact on regional and global atmospheric circulation patterns. These patterns, in turn, affect processes such as precipitation, erosion, and sedimentation. Over the last two decades, various geochemical, geomorphologic, and geologic approaches have helped identify when, where, and how quickly topography has risen in the past. The current spatio-temporal picture of Central Andean growth is now providing insight into which deep-Earth processes have left their imprint on the shape of the Earth's surface. KW - paleoaltimetry KW - stable isotopes KW - relief development KW - river incision KW - landscape evolution Y1 - 2018 U6 - https://doi.org/10.2138/gselements.14.4.231 SN - 1811-5209 SN - 1811-5217 VL - 14 IS - 4 SP - 231 EP - 236 PB - Mineralogical Society of America CY - Chantilly ER - TY - JOUR A1 - Landgraf, Angela A1 - Zielke, Olaf A1 - Arrowsmith, J. Ramón A1 - Ballato, Paolo A1 - Strecker, Manfred A1 - Schildgen, Taylor F. A1 - Friedrich, Anke M. A1 - Tabatabaei, Sayyed-Hassan T1 - Differentiating simple and composite tectonic landscapes using numerical fault slip modeling with an example from the south central Alborz Mountains, Iran JF - Journal of geophysical research : Earth surface N2 - The tectonically driven growth of mountains reflects the characteristics of the underlying fault systems and the applied tectonic forces. Over time, fault networks might be relatively static, but stress conditions could change and result in variations in fault slip orientation. Such a tectonic landscape would transition from a simple to a composite state: the topography of simple landscapes is correlated with a single set of tectonic boundary conditions, while composite landscapes contain inherited topography due to earlier deformation under different boundary conditions. We use fault interaction modeling to compare vertical displacement fields with topographic metrics to differentiate the two types of landscapes. By successively rotating the axis of maximum horizontal stress, we produce a suite of vertical displacement fields for comparison with real landscapes. We apply this model to a transpressional duplex in the south central Alborz Mountains of Iran, where NW oriented compression was superseded by neotectonic NE compression. The consistency between the modeled displacement field and real landforms indicates that the duplex topography is mostly compatible with the modern boundary conditions, but might include a small remnant from the earlier deformation phase. Our approach is applicable for various tectonic settings and represents an approach to identify the changing boundary conditions that produce composite landscapes. It may be particularly useful for identifying changes that occurred in regions where river profiles may no longer record a signal of the change or where the spatial pattern of uplift is complex. KW - fault interaction KW - landscape evolution KW - numerical modeling KW - Alborz Mountains KW - Iran Y1 - 2013 U6 - https://doi.org/10.1002/jgrf.20109 SN - 2169-9003 SN - 2169-9011 VL - 118 IS - 3 SP - 1792 EP - 1805 PB - American Geophysical Union CY - Washington ER -