Overriding plate shortening and extension above subduction zones: A parametric study to explain formation of the Andes Mountains

Abstract

Research Article| November 01, 2008 Overriding plate shortening and extension above subduction zones: A parametric study to explain formation of the Andes Mountains W.P. Schellart W.P. Schellart 1Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia †Present address: School of Geosciences, Monash University, Melbourne, VIC 3800, Australia. E-mail: wouter.schellart@sci.monash.edu.au; tel: 61 (0)3 9905 1782; fax: 61 (0)3 9905 4903. Search for other works by this author on: GSW Google Scholar GSA Bulletin (2008) 120 (11-12): 1441–1454. https://doi.org/10.1130/B26360.1 Article history received: 06 Nov 2007 rev-recd: 29 Feb 2008 accepted: 10 Mar 2008 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 W.P. Schellart; Overriding plate shortening and extension above subduction zones: A parametric study to explain formation of the Andes Mountains. GSA Bulletin 2008;; 120 (11-12): 1441–1454. doi: https://doi.org/10.1130/B26360.1 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 SocietyGSA Bulletin Search Advanced Search Abstract Mountain building above subduction zones, such as observed in the Andes, is enigmatic, and the key parameter controlling the underlying dynamics remains a matter of considerable debate. A global survey of subduction zones is presented here, illustrating the correlation between overriding plate deformation rate and twelve physical parameters: overriding plate velocity, subducting plate velocity, trench velocity, convergence velocity, subduction velocity, subduction zone accretion rate, subducting plate age, subduction polarity, shallow slab dip, deep slab dip, lateral slab edge proximity, and subducting ridge proximity. All correlation coefficients are low (|R| ≤ 0.39), irrespective of the global reference frame, relative plate motion model, or overriding plate deformation model, except for the trench velocity (0.33–0.68, exact value depends on adopted global reference frame) and subduction velocity, which shows an anticorrelation (0.55–0.57). This implies that no individual parameter can explain overriding plate deformation, except that trench retreat generally corresponds to extension while an approximately stable trench or trench advance generally corresponds to shortening. Understanding of the variety of strain patterns is obtained when slab edge proximity and overriding plate velocity are combined. Orogenesis occurs in overriding plates bordering central regions of wide subduction zones (≥~4000 km) when the overriding plate is moving trenchward at 0–2 cm/yr (e.g., Andes, Japan). Because the center of a wide slab offers large resistance to lateral migration, the overriding plate effectively collides with the subduction hinge, forcing the slab to attain a shallow dip angle (e.g., Nazca and Japan slabs). Overriding plate extension is only found close to lateral slab edges or during overriding plate motion away from the center of a wide subduction zone, but in the latter scenario, maximum extension velocities are much lower than in the former scenario. For subduction settings close to lateral slab edges, overriding plate motion plays no significant role in overriding plate deformation. Thus, for rapid overriding plate extension, the key ingredient is rapid trench retreat, which only occurs close to lateral slab edges, while for overriding plate shortening, the key ingredients are (1) the resistance to rapid trench and hinge retreat, which occurs far from lateral slab edges, and (2) trenchward overriding plate motion. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.