The dike swarm of the Karakoram shear zone, Ladakh, NW India: Linking granite source to batholith

Abstract

Research Article| January 01, 2012 The dike swarm of the Karakoram shear zone, Ladakh, NW India: Linking granite source to batholith Henning Reichardt; Henning Reichardt † School of Geosciences, Monash University, Building 28, Clayton, VIC 3800, Australia †E-mail: henning.reichardt@monash.edu Search for other works by this author on: GSW Google Scholar Roberto F. Weinberg Roberto F. Weinberg School of Geosciences, Monash University, Building 28, Clayton, VIC 3800, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information Henning Reichardt † School of Geosciences, Monash University, Building 28, Clayton, VIC 3800, Australia Roberto F. Weinberg School of Geosciences, Monash University, Building 28, Clayton, VIC 3800, Australia †E-mail: henning.reichardt@monash.edu Publisher: Geological Society of America Received: 14 Aug 2010 Revision Received: 02 Jan 2011 Accepted: 06 Jan 2011 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2012 Geological Society of America GSA Bulletin (2012) 124 (1-2): 89–103. https://doi.org/10.1130/B30394.1 Article history Received: 14 Aug 2010 Revision Received: 02 Jan 2011 Accepted: 06 Jan 2011 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Henning Reichardt, Roberto F. Weinberg; The dike swarm of the Karakoram shear zone, Ladakh, NW India: Linking granite source to batholith. GSA Bulletin 2012;; 124 (1-2): 89–103. doi: https://doi.org/10.1130/B30394.1 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 Debate regarding migration of granitic magmas arises from the fact that the physical link between migmatites and plutons and batholiths is rarely documented. Within the Karakoram shear zone, Ladakh, NW India, the synkinematic transfer of magma can be traced from the anatectic source region to the Karakoram Batholith through a complex dike swarm. Melting is due to water fluxing at upper-amphibolite facies, producing Miocene hornblende and garnet–two mica leucogranites. The anatectic zone is characterized by synmagmatic folding and shearing of migmatites, and by pervasive, irregular magma migration paths forming injection complexes. These irregular networks are linked to dike networks that are interpreted to represent a magma transfer zone characterized by a range of styles, such as (1) dike swarms parallel to the shear plane, (2) dikes following the two major foliation planes in the shear fabric, (3) magma sheets in conjugate pairs of ductile fractures, or (4) chaotic dike complexes. Network geometries are controlled by the regional stress field, strain distribution, preexisting anisotropies, and rheological contrasts. Dikes give rise to anastomosing systems with rare crosscutting relationships, and with intersections oriented parallel to the dominant mineral stretching lineation. Dikes feed a number of sills, stocks, plutons, and, ultimately, the leucogranitic Karakoram Batholith. We propose that magma developed an interlinked, continuous dike swarm from source to sink by interacting with deformation and preexisting anisotropies. Unlike theoretical and laboratory predictions, dikes are typically oriented at high angles to the maximum shortening axis, and unlike expectations, water-fluxed melting of the crust produced mobile magma that migrated to form large granitic bodies. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.