Neogene climate change and uplift in the Atacama Desert, Chile

Abstract

Research Article| September 01, 2006 Neogene climate change and uplift in the Atacama Desert, Chile Jason A. Rech; Jason A. Rech 1Department of Geology, Miami University, Oxford, Ohio 45056, USA Search for other works by this author on: GSW Google Scholar Brian S. Currie; Brian S. Currie 1Department of Geology, Miami University, Oxford, Ohio 45056, USA Search for other works by this author on: GSW Google Scholar Greg Michalski; Greg Michalski 2Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907, USA Search for other works by this author on: GSW Google Scholar Angela M. Cowan Angela M. Cowan 3Department of Geology, Miami University, Oxford, Ohio 45056, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Jason A. Rech 1Department of Geology, Miami University, Oxford, Ohio 45056, USA Brian S. Currie 1Department of Geology, Miami University, Oxford, Ohio 45056, USA Greg Michalski 2Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907, USA Angela M. Cowan 3Department of Geology, Miami University, Oxford, Ohio 45056, USA Publisher: Geological Society of America Received: 18 Nov 2005 Revision Received: 07 Apr 2006 Accepted: 25 Apr 2006 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2006) 34 (9): 761–764. https://doi.org/10.1130/G22444.1 Article history Received: 18 Nov 2005 Revision Received: 07 Apr 2006 Accepted: 25 Apr 2006 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Jason A. Rech, Brian S. Currie, Greg Michalski, Angela M. Cowan; Neogene climate change and uplift in the Atacama Desert, Chile. Geology 2006;; 34 (9): 761–764. doi: https://doi.org/10.1130/G22444.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The relationship between Andean uplift and extreme desiccation of the west coast of South America is important for understanding the interplay between climate and tectonics in the Central Andes, yet it is poorly understood. Here we use soil morphological characteristics, salt chemistry, and mass independent fractionation anomalies (Δ17O values) in dated paleosols to reconstruct a middle Miocene climatic transition from semiaridity to extreme hyperaridity in the Atacama Desert. Paleosols along the southeastern margin of the Calama Basin change from calcic Vertisols with root traces, slickensides, and gleyed horizons to an extremely mature salic Gypsisol with pedogenic nitrate. We interpret this transition, which occurred between 19 and 13 Ma, to represent a change in precipitation from >200 mm/yr to <20 mm/yr. This drastic reduction in precipitation likely resulted from uplift of the Central Andes to elevations >2 km; the uplift blocked moisture from the South American summer monsoon from entering the Atacama. The mid-Miocene Gypsisol with pedogenic nitrate is located at elevations between 2900 and 3400 m in the Calama Basin, significantly higher than modern nitrate soils, which occur below ∼2500 m. Modern and Quaternary soils in this elevation zone contain soil carbonate and lack pedogenic gypsum and nitrate. We infer that >900 m of local surface uplift over the past 10 m.y. displaced these nitrate paleosols relative to modern nitrate soils and caused a return to wetter conditions in the Calama Basin by decreasing local air temperatures and creating an orographic barrier to Pacific air masses. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.