Research Article| March 01, 2010 Effect of late Cenozoic aridification on sedimentation in the Eastern Cordillera of northwest Argentina (Angastaco basin) Sharon Bywater-Reyes; Sharon Bywater-Reyes 1Department of Geology and Geophysics, University of Wyoming, 1000 E University Avenue, Laramie, Wyoming 82071, USA Search for other works by this author on: GSW Google Scholar Barbara Carrapa; Barbara Carrapa 1Department of Geology and Geophysics, University of Wyoming, 1000 E University Avenue, Laramie, Wyoming 82071, USA Search for other works by this author on: GSW Google Scholar Mark Clementz; Mark Clementz 1Department of Geology and Geophysics, University of Wyoming, 1000 E University Avenue, Laramie, Wyoming 82071, USA Search for other works by this author on: GSW Google Scholar Lindsay Schoenbohm Lindsay Schoenbohm 2School of Earth Sciences, Ohio State University, 275 Mendenhall Laboratory, 125 South Oval Mall, Columbus, Ohio 43210, USA Search for other works by this author on: GSW Google Scholar Geology (2010) 38 (3): 235–238. https://doi.org/10.1130/G30532.1 Article history received: 16 Jul 2009 rev-recd: 08 Oct 2009 accepted: 14 Oct 2009 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Sharon Bywater-Reyes, Barbara Carrapa, Mark Clementz, Lindsay Schoenbohm; Effect of late Cenozoic aridification on sedimentation in the Eastern Cordillera of northwest Argentina (Angastaco basin). Geology 2010;; 38 (3): 235–238. doi: https://doi.org/10.1130/G30532.1 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 This study evaluates the effect of climate on facies, grain size, and sedimentation rates using sedimentology, geochronology, and stable isotope geochemistry for Miocene–Pliocene deposits in the Angastaco basin (Eastern Cordillera, northwest Argentina). U-Pb zircon data from ash layers constrain the transition between the finer grained fluvial-lacustrine Palo Pintado Formation and the coarser grained fluvial-alluvial San Felipe Formation to ca. 5.2 Ma and the first deposition of sediment derived from the present-day orographic barrier to ca. 4 Ma. δ13C values from pedogenic carbonate nodules range from −15.4‰ to −10.2‰ for the Palo Pintado Formation and from −9.5‰ to −8.2‰ for the San Felipe Formation; this can be best explained by increased, sustained aridity since ca. 5 Ma. The δ18O values range from −9.6‰ to −5.9‰ for the Palo Pintado Formation and from −6.1‰ to −5.2‰ for the San Felipe Formation, corroborating this interpretation. The shift toward more arid conditions correlates with a significant increase in grain size but no significant change in sedimentation rate. Because aridity precedes the development of an orographic effect, we interpret the grain size increase in the Angastaco basin since ca. 5 Ma to be a response of the sedimentary system to aridification resulting from regional climate change. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.