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

Evenstar, L. A., Stuart, F. M. , Hartley, A. J. and Tattitch, B. (2015) Slow Cenozoic uplift of the western Andean Cordillera indicated by cosmogenic 3He in alluvial boulders from the Pacific Planation Surface. Geophysical Research Letters, 42(20), pp. 8448-8455. (doi: 10.1002/2015GL065959)

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 was 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 modeled 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 Myr ago.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Stuart, Professor Fin
• Authors: Evenstar, L. A., Stuart, F. M., Hartley, A. J., and Tattitch, B.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Geophysical Research Letters
• Publisher: American Geophysical Union
• ISSN: 0094-8276
• ISSN (Online): 1944-8007
• Published Online: 12 October 2015
• Copyright Holders: Copyright © 2015 The Authors
• First Published: First published in Geophysical Research Letters 42(20):8448-8455
• Publisher Policy: Reproduced under a Creative Commons License