TY - JOUR A1 - Roda-Boluda, Duna C. A1 - Whittaker, Alexander C. A1 - Gheorghiu, Delia M. A1 - Rodes, Angel A1 - D'Arcy, Mitch T1 - Be-10 erosion rates controlled by transient response to normal faulting through incision and landsliding JF - Earth & planetary science letters N2 - Quantifying erosion rates, and how they compare to rock uplift rates, is fundamental for understanding landscape response to tectonics and associated sediment fluxes from upland areas. The erosional response to uplift is well-represented by river incision and the associated landslide activity. However, characterising the relationship between these processes remains a major challenge in tectonically active areas, in some cases because landslides can preclude obtaining reliable erosion rates from cosmogenic radionuclide (CRN) concentrations. Here, we quantify the control of tectonics and its coupled geomorphic response on the erosion rates of catchments in southern Italy that are experiencing a transient response to normal faulting. We analyse in-situ Be-10 concentrations for detrital sediment samples, collected along the strike of faults with excellent tectonic constraints and landslide inventories. We demonstrate that Be-10-derived erosion rates are controlled by fault throw rates and the extent of transient incision and associated landsliding in the catchments. We show that the low-relief sub-catchments above knickpoints erode at uniform background rates of similar to 0.10 mm/yr, while downstream of knickpoints, erosion removes similar to 50% of the rock uplifted by the faults, at rates of 0.10-0.64 mm/yr. Despite widespread landsliding, CRN samples provide relatively consistent and accurate erosion rates, most likely because landslides are frequent, small, and shallow, and represent the integrated record of landsliding over several seismic cycles. Consequently, we combine these validated Be-10 erosion rates and data from a geomorphological landslide inventory in a published numerical model, to gain further insight into the long-term landslide rates and sediment mixing, highlighting the potential of CRN data to study landslide dynamics. (C) 2018 Elsevier B.V. All rights reserved. KW - cosmogenic nuclides KW - erosion rates KW - normal faults KW - incision KW - landslides KW - transient response Y1 - 2019 U6 - https://doi.org/10.1016/j.epsl.2018.11.032 SN - 0012-821X SN - 1385-013X VL - 507 SP - 140 EP - 153 PB - Elsevier CY - Amsterdam ER - 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 -