Slow rates of subduction erosion and coastal underplating along the Andean margin of Chile and Peru

Abstract

Research Article| June 01, 2007 Slow rates of subduction erosion and coastal underplating along the Andean margin of Chile and Peru Peter D. Clift; Peter D. Clift 1Department of Geology and Petroleum Geology, School of Geosciences, Meston Building, University of Aberdeen, Aberdeen AB24 3UE, UK Search for other works by this author on: GSW Google Scholar Adrian J. Hartley Adrian J. Hartley 1Department of Geology and Petroleum Geology, School of Geosciences, Meston Building, University of Aberdeen, Aberdeen AB24 3UE, UK Search for other works by this author on: GSW Google Scholar Geology (2007) 35 (6): 503–506. https://doi.org/10.1130/G23584A.1 Article history received: 18 Dec 2006 rev-recd: 12 Jan 2007 accepted: 16 Jan 2007 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 Peter D. Clift, Adrian J. Hartley; Slow rates of subduction erosion and coastal underplating along the Andean margin of Chile and Peru. Geology 2007;; 35 (6): 503–506. doi: https://doi.org/10.1130/G23584A.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 Marine seismic and drilling data from the Andean margin of Peru and northern Chile show trench retreat and tectonic erosion since at least 20 Ma. However, the onshore coastal zone has undergone modest regional uplift since ca. 2 Ma. This argues against subduction erosion of the margin by steady-state retreat, such as recognized in Tonga or South Sandwich. Instead we identify a new style of slow tectonic erosion. Uplifted forearc sediments indicate underplating of subducted material beneath the base of the coastal forearc, synchronous with tectonic erosion under the trenchward part of the forearc. These observations require slow rates of forearc crust subduction in the region during this time period, averaging no more than 13 km3/m.y./km since 20 Ma as the forearc wedge taper increased. Isostatic volume estimates suggest that as much as 85% of subducted material was underplated under the forearc since 330 ka and does not contribute to crustal growth under the Andes. The switch in tectonic style parallels that in the southern Andes, but cannot be triggered by increased sediment flux to the trench, as proposed for that area. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.