Quaternary tectonic and denudation rates are investigated for an actively growing basement anticline: the Sierra Pie de Palo range, which belongs to the Andean foreland of Northwestern Argentina (28 • S-33 • S). In this study, a detailed morphometric analysis of the topography is combined with in situ-produced cosmogenic 10 Be concentrations measured in (1) surface boulders abandoned on alluvial terraces affected by fault activity (along the north bounding fault) and growth of the basement fold (along the southeastern border), (2) bedrock outcrops corresponding to an exhumed and folded, regional erosion surface, and (3) fluvial sediments sampled at the outlets of several watersheds. Along the eastern and northern borders of the range, incision and uplift rates have been estimated at approximately 0.5 and 1 mm/yr when integrated on Holocene and Pleistocene time scales, in close agreement with both long-term (structural and basin evolution data) and short-term (GPS-derived velocity field) analyses. Cosmogenic-derived denudation and uplift rates combined with geomorphic characteristics of watersheds and river channels allows estimating the onset of the uplift at 4-6 Ma, followed by a more recent period of topographic rejuvenation at roughly 1-2 Ma, probably synchronous with steepening of the eastern and northern flanks of the anticline.

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Sixty-eight 10 Be terrestrial cosmogenic nuclide (TCN) surface exposure ages are presented to define the timing of alluvial fan and strath terrace formation in the hyper-arid San Juan region of the Argentine Precordillera. This region is tectonically active, and numerous fault scarps traverse Quaternary landforms. The three study sites, Marquesado strath complex, Loma Negra alluvial fan and Carpintería strath complex reveal a history of alluvial fan and strath terrace development over the past w225 ka. The Marquesado complex Q3 m surface dates to w17 AE 3 ka, whereas the Loma Negra Q1 ln , Q2 ln , Q3 ln , Q4 ln , and Q5 ln surfaces date to w24 AE 3 ka, w48 AE 2 ka, w65 AE 13 ka, w105 AE 21 ka, and w181 AE 29 ka, respectively. The Carpintería complex comprises eight surfaces that have been dated and include the Q1 c (w23 AE 3 ka), Q2 c (w5 AE 5 ka), Q3a c (w25 AE 12 ka), Q3b c (w29 AE 15 ka), Q4 c (w61 AE 12 ka), Q5 c (w98 AE 18 ka), Q6 c (w93 AE 18 ka), and Q7 c (w212 AE 37 ka). 10 Be TCN depth profile data for the Loma Negra alluvial fan complex and Carpintería strath terrace complex, as well as OSL ages on some Carpintería deposits, aid in refining surface ages for comparison with local and global climate proxies, and additionally offer insights into inheritance and erosion rate values for TCNs (w10 Â 10 4 10 Be atoms/g of SiO 2 and w5 m Ma À1 , respectively). Comparison with other alluvial fan studies in the region show that less dynamic and older preserved surfaces occur in the Carpintería and Loma Negra areas with only younger alluvial fan surfaces preserved both to the north and south. These data in combination with that of other studies illustrate broad regional agreement between alluvial fan and strath terrace ages, which suggests that climate is the dominant forcing agent in the timing of terrace formation in this region.