Balancing crustal thickening in arcs by tectonic vs. magmatic means

Abstract

Research Article| November 01, 2003 Balancing crustal thickening in arcs by tectonic vs. magmatic means M. Haschke; M. Haschke 1GeoForschungsZentrum, Telegrafenberg, Potsdam 14473, Germany Search for other works by this author on: GSW Google Scholar A. Günther A. Günther 2Institut für Umweltgeologie, Technische Universität Braunschweig, Braunschweig 38106, Germany Search for other works by this author on: GSW Google Scholar Author and Article Information M. Haschke 1GeoForschungsZentrum, Telegrafenberg, Potsdam 14473, Germany A. Günther 2Institut für Umweltgeologie, Technische Universität Braunschweig, Braunschweig 38106, Germany Publisher: Geological Society of America Received: 18 Jun 2003 Revision Received: 28 Jul 2003 Accepted: 28 Jul 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2003) 31 (11): 933–936. https://doi.org/10.1130/G19945.1 Article history Received: 18 Jun 2003 Revision Received: 28 Jul 2003 Accepted: 28 Jul 2003 First Online: 02 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 M. Haschke, A. Günther; Balancing crustal thickening in arcs by tectonic vs. magmatic means. Geology 2003;; 31 (11): 933–936. doi: https://doi.org/10.1130/G19945.1 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 Igneous intrusions were emplaced prior to and contemporaneous with horizontal shortening of the crust in the Late Cretaceous to late Eocene magmatic arc in north Chile (21°45′–22°30′S). Temporally changing major and trace elements of magmatic rocks from this paleo–arc system chronicled gradual crustal thickening prior to and substantial crustal thickening contemporaneously with crustal shortening. Balanced structural cross sections indicate a minimum of 9 km of arc-normal shortening that occurred simultaneously with dextral arc-parallel movements accounting for orogen-parallel lengthening of ∼10 km. This shortening produced ∼5.4 km of tectonic crustal thickening and resulted in a minimum of ∼42 km late Eocene Andean crustal thickness. Temporal and spatial geochemical changes diagnostic of crustal thickening indicate that the remainder (∼2.6 km) was accommodated by basaltic underplating at or near the base of the arc crust prior to and during transpression. The ratio of tectonic to magmatic crustal thickening is ∼2:1. Whole-crustal magmatic addition rates during the ∼12 m.y. duration of arc transpression are ∼35 km3 per kilometer of model arc length per million years. Mafic underplating may have thickened the Andean crust considerably, but most pre-Neogene crustal thickening was due to discrete episodes of tectonic shortening. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.