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Publication - Dr Brian Tattitch

    Slow Cenozoic uplift of the western Andean Cordillera indicated by cosmogenic ³He in alluvial boulders from the Pacific Planation Surface

    Slow Cenozoic uplift of the Andes

    Citation

    Evenstar, LA, Stuart, F, Hartley, A & Tattitch, BC, 2015, ‘Slow Cenozoic uplift of the western Andean Cordillera indicated by cosmogenic ³He in alluvial boulders from the Pacific Planation Surface: Slow Cenozoic uplift of the Andes ’. Geophysical Research Letters, vol 42., pp. 8448-8455

    Abstract

    To determine the mechanisms responsible for mountain belt growth it is important to accurately establish the timing of surface uplift. Here we exploit the altitude control on the production rate of in situ cosmogenic nuclides to test the hypothesis that the Andes were uplifted in the late Miocene. High concentrations of in situ cosmogenic 3He (3Hecos) have previously been measured in alluvial boulders on the western flank of the Central Andes, northern Chile (Evenstar et al. 2009). These are consistent with deposition soon after formation of the surface (13-14 Ma). We have modelled the accumulation of cosmogenic 3He in several different surface uplift scenarios and compared them to the measured concentrations. The measured 3Hecos concentrations are too high to be produced by late Miocene uplift and imply that the western flank of the Andean Cordillera attained a substantial part of its current elevation prior to 14 million years ago.

    Full details in the University publications repository