Evidence for a Western Extracontinental Land Source During the Devonian Period in the Central Andes

Abstract

Research Article| January 01, 1975 Evidence for a Western Extracontinental Land Source During the Devonian Period in the Central Andes PETER E. ISAACSON PETER E. ISAACSON 1Department of Geology, Oregon State University, Corvallis, Oregon 97331. Present address: Department of Geology, University of Massachusetts, Amherst, Massachusetts 01002. Search for other works by this author on: GSW Google Scholar Author and Article Information PETER E. ISAACSON 1Department of Geology, Oregon State University, Corvallis, Oregon 97331. Present address: Department of Geology, University of Massachusetts, Amherst, Massachusetts 01002. Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1975) 86 (1): 39–46. https://doi.org/10.1130/0016-7606(1975)86<39:EFAWEL>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation PETER E. ISAACSON; Evidence for a Western Extracontinental Land Source During the Devonian Period in the Central Andes. GSA Bulletin 1975;; 86 (1): 39–46. doi: https://doi.org/10.1130/0016-7606(1975)86<39:EFAWEL>2.0.CO;2 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 SocietyGSA Bulletin Search Advanced Search Abstract A large intracratonic sedimentary basin of mid-Paleozoic age in the central Andes apparently received sediments from a western land source. Lithofacies and isopach data show a thickening and general textural coarsening to the north and west in the Devonian rocks of Bolivia. Early to early Middle Devonian onlap and offlap are recognized. Rate of subsidence in the basin was only slightly exceeded by rate of sedimentation, because the youngest Devonian beds recognized are either very shallow marine (in southern localities) or nonmarine (in at least one northern locality). Devonian brachiopod community studies suggest that a shallow marine environment persisted in the region throughout the time of deposition of the Devonian rocks. An absence of bedded carbonate rocks indicates a cold-climate environment of deposition. It is suggested that the source area yielded abundant muscovite. Outcrops of sialic basement relicts in the Cordillera Occidental are concluded to be portions of a buried land mass. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.