Inversion of forearc basins in south-central Chile caused by rapid glacial age trench fill

Abstract

Research Article| September 01, 2006 Inversion of forearc basins in south-central Chile caused by rapid glacial age trench fill Daniel Melnick; Daniel Melnick 1GeoForschungsZentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany Search for other works by this author on: GSW Google Scholar Helmut P. Echtler Helmut P. Echtler 1GeoForschungsZentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany Search for other works by this author on: GSW Google Scholar Geology (2006) 34 (9): 709–712. https://doi.org/10.1130/G22440.1 Article history 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 Daniel Melnick, Helmut P. Echtler; Inversion of forearc basins in south-central Chile caused by rapid glacial age trench fill. Geology 2006;; 34 (9): 709–712. doi: https://doi.org/10.1130/G22440.1 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 examines the response of a forearc to the increase in sediment flux to the trench caused by the onset of glacial denudation in the Patagonian Andes. We investigated shelf-coastal basins in south-central Chile, which generally comprise Eocene–early Miocene nearshore facies overlain by late Miocene–early Pliocene deep-water siltstones and by late Pliocene–Quaternary nearshore deposits. Seismic profiles and coastal exposures reveal Eocene–early Pliocene extension followed by ongoing late Pliocene compression evidenced from growth strata adjacent to seismically active reverse faults. The onset of major global cooling ca. 6 Ma triggered glacial denudation in the uplifted high Andes. Exhumed material transported along the steep and humid Andean western slope increased trench sedimentation rates and caused continuous accretion and subduction of terrigenous material. We interpret forearc basin inversion as a response to a decrease in slope and basal friction of the wedge caused by frontal accretion and subduction of water-rich material, respectively, in order to reach a critical taper. This process lifted the shelf ∼1.5 km during the middle Pliocene. The Juan Fernández Ridge and Chile Rise confined >2 km trench fill between 45 and 34°S, limiting accretion and basin inversion. Glacial age trench fill and the steady decrease in plate convergence rate shifted this segment of the margin from erosive to accretionary during the Pliocene. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.