Geometry and crustal shortening of the Himalayan fold-thrust belt, eastern and central Bhutan

Abstract

Research Article| July 01, 2011 Geometry and crustal shortening of the Himalayan fold-thrust belt, eastern and central Bhutan Sean Long; Sean Long † 1Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA †E-mail: [e-mail] Search for other works by this author on: GSW Google Scholar Nadine McQuarrie; Nadine McQuarrie 1Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA Search for other works by this author on: GSW Google Scholar Tobgay Tobgay; Tobgay Tobgay 1Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA Search for other works by this author on: GSW Google Scholar Djordje Grujic Djordje Grujic 2Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4J1, Canada Search for other works by this author on: GSW Google Scholar GSA Bulletin (2011) 123 (7-8): 1427–1447. https://doi.org/10.1130/B30203.1 Article history received: 29 Oct 2009 rev-recd: 21 Jan 2010 accepted: 25 Jan 2010 first online: 08 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 Sean Long, Nadine McQuarrie, Tobgay Tobgay, Djordje Grujic; Geometry and crustal shortening of the Himalayan fold-thrust belt, eastern and central Bhutan. GSA Bulletin 2011;; 123 (7-8): 1427–1447. doi: https://doi.org/10.1130/B30203.1 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 We present a new geologic map of eastern and central Bhutan and four balanced cross sections through the Himalayan fold-thrust belt. Major structural features, from south to north, include: (1) a single thrust sheet of Subhimalayan rocks above the Main Frontal thrust; (2) the upper Lesser Himalayan duplex system, which repeats horses of the Neoproterozoic–Cambrian(?) Baxa Group below a roof thrust (Shumar thrust) carrying the Paleoproterozoic Daling-Shumar Group; (3) the lower Lesser Himalayan duplex system, which repeats horses of the Daling-Shumar Group and Neoproterozoic–Ordovician(?) Jaishidanda Formation, with the Main Central thrust (MCT) acting as the roof thrust; (4) the structurally lower Greater Himalayan section above the MCT with overlying Tethyan Himalayan rock in stratigraphic contact in central Bhutan and structural contact above the South Tibetan detachment in eastern Bhutan; and (5) the structurally higher Greater Himalayan section above the Kakhtang thrust. Cross sections show 164–267 km shortening in Subhimalayan and Lesser Himalayan rocks, 97–156 km structural overlap across the MCT, and 31–53 km structural overlap across the Kakhtang thrust, indicating a total of 344–405 km of minimum crustal shortening (70%–75%). Our data show an eastward continuation of Lesser Himalayan duplexing identified in northwest India, Nepal, and Sikkim, which passively folded the overlying Greater Himalayan and Tethyan Himalayan sections. Shortening and percent shortening estimates across the orogen, although minima, do not show an overall eastward increase, which may suggest that shortening variations are controlled more by the original width and geometry of the margin than by external parameters such as erosion and convergence rates. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.