Portal de Periódicos da CAPES

Synorogenic extension: Quantitative constraints on the age and displacement of the Zanskar shear zone (northwest Himalaya)

1999; Geological Society of America; Volume: 111; Issue: 3 Linguagem: Inglês

10.1130/0016-7606(1999)111 2.3.co;2

1943-2674

P. Dèzes, Jean‐Claude Vannay, A. Steck, F. Bussy, Michael A. Cosca,

High-pressure geophysics and materials

Research Article| March 01, 1999 Synorogenic extension: Quantitative constraints on the age and displacement of the Zanskar shear zone (northwest Himalaya) P. J. Dézes; P. J. Dézes 1Institut de Minéralogie, Université de Lausanne, BFSH2, CH-1015 Lausanne, Switzerland Search for other works by this author on: GSW Google Scholar J.-C. Vannay; J.-C. Vannay 1Institut de Minéralogie, Université de Lausanne, BFSH2, CH-1015 Lausanne, Switzerland Search for other works by this author on: GSW Google Scholar A. Steck; A. Steck 1Institut de Minéralogie, Université de Lausanne, BFSH2, CH-1015 Lausanne, Switzerland Search for other works by this author on: GSW Google Scholar F. Bussy; F. Bussy 1Institut de Minéralogie, Université de Lausanne, BFSH2, CH-1015 Lausanne, Switzerland2Geochronology Laboratory, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada Search for other works by this author on: GSW Google Scholar M. Cosca M. Cosca 1Institut de Minéralogie, Université de Lausanne, BFSH2, CH-1015 Lausanne, Switzerland Search for other works by this author on: GSW Google Scholar GSA Bulletin (1999) 111 (3): 364–374. https://doi.org/10.1130/0016-7606(1999)111 2.3.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation P. J. Dézes, J.-C. Vannay, A. Steck, F. Bussy, M. Cosca; Synorogenic extension: Quantitative constraints on the age and displacement of the Zanskar shear zone (northwest Himalaya). GSA Bulletin 1999;; 111 (3): 364–374. doi: https://doi.org/10.1130/0016-7606(1999)111 2.3.CO;2 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 Structural, thermobarometric, and geochronological data place limits on the age and tectonic displacement along the Zanskar shear zone, a major north-dipping synorogenic extensional structure separating the high-grade metamorphic sequence of the High Himalayan Crystalline Sequence from the overlying low-grade sedimentary rocks of the Tethyan Himalaya. A complete Barrovian metamorphic succession, from kyanite to biotite zone mineral assemblages, occurs within the 1-km-thick Zanskar shear zone. Thermobarometric data indicate a difference in equilibration depths of 12 ± 3 km between the lower kyanite zone and the garnet zone, which is interpreted as a minimum estimate for the finite vertical displacement accommodated by the Zanskar shear zone. For the present-day dip of the structure (20°), a simple geometrical model shows that a net slip of 35 ± 9 km is required to regroup these samples to the same structural level. Because the kyanite to garnet zone rocks represent only part of the Zanskar shear zone, and because its original dip may have been less than the present-day dip, these estimates for the finite displacement represent minimum values. Field relations and petrographic data suggest that migmatization and associated leucogranite intrusion in the footwall of the Zanskar shear zone occurred as a continuous process starting at the Barrovian metamorphic peak and lasting throughout the subsequent extension-induced exhumation. Geochronological dating of various leucogranitic plutons and dikes in the Zanskar shear zone footwall indicates that the main ductile shearing along the structure ended by 19.8 Ma and that extension most likely initiated shortly before 22.2 Ma. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.