Mesoproterozoic plate tectonics: A collisional model for the Grenville-aged orogenic belt in the Llano uplift, central Texas

Abstract

Research Article| January 01, 2008 Mesoproterozoic plate tectonics: A collisional model for the Grenville-aged orogenic belt in the Llano uplift, central Texas S. Mosher; S. Mosher 1Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78712, USA Search for other works by this author on: GSW Google Scholar J.S.F. Levine; J.S.F. Levine 1Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78712, USA Search for other works by this author on: GSW Google Scholar W.D. Carlson W.D. Carlson 1Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78712, USA Search for other works by this author on: GSW Google Scholar Geology (2008) 36 (1): 55–58. https://doi.org/10.1130/G24049A.1 Article history received: 01 May 2007 rev-recd: 05 Sep 2007 accepted: 06 Sep 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 S. Mosher, J.S.F. Levine, W.D. Carlson; Mesoproterozoic plate tectonics: A collisional model for the Grenville-aged orogenic belt in the Llano uplift, central Texas. Geology 2008;; 36 (1): 55–58. doi: https://doi.org/10.1130/G24049A.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 The Llano uplift of central Texas, United States, exposes the core of a Mesoproterozoic orogenic belt that formed along the southern margin of Laurentia during Grenville time. A new collisional model is proposed that reconciles differences in structural stacking, apparent tectonic transport, and deformation conditions between the eastern and western portions of the uplift and explains uplift and exhumation of high-pressure eclogitic rocks, emplacement of ophiolitic rocks, and subsequent late-stage to postcollisional plutonism. Our model proposes that subduction with southward polarity resulted in collision of an exotic arc with Laurentia, emplacement of ophiolitic rocks, and telescoping of the intervening basinal sediments, followed by overriding of the arc and margin of Laurentia by a southern continent with transport toward Laurentia. The model further proposes that convergence led to subduction of the Laurentian margin, resulting in high-pressure metamorphism, but buoyancy forces due to subduction of continental crust under the southern continent resulted in uplift and retrotransport away from Laurentia, in a manner similar to that proposed for the Alpine orogeny. Slab breakoff resulted in upwelling of the asthenosphere, leading to intrusion of juvenile granitic plutons. Subduction along strike caused continued contraction that waned with time. The eastern uplift records continent-arc-continent collision, whereas the western uplift records continent-continent collision; the two regions also expose different crustal levels in the orogen. The striking similarity with Phanerozoic orogens, including emplacement of ophiolites and formation of high-pressure rocks, implies that plate tectonic processes including subduction were active prior to the Neoproterozoic. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.