Relationships between displacement and distortion in orogens: Linking the Himalayan foreland and hinterland in central Nepal

Abstract

Research Article| July 01, 2010 Relationships between displacement and distortion in orogens: Linking the Himalayan foreland and hinterland in central Nepal Kyle P. Larson; Kyle P. Larson † Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada †Current address: Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada; e-mail: kyle.larson@usask.ca. Search for other works by this author on: GSW Google Scholar Laurent Godin; Laurent Godin Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada Search for other works by this author on: GSW Google Scholar Raymond A. Price Raymond A. Price Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada Search for other works by this author on: GSW Google Scholar GSA Bulletin (2010) 122 (7-8): 1116–1134. https://doi.org/10.1130/B30073.1 Article history received: 13 Apr 2009 rev-recd: 21 Aug 2009 accepted: 22 Aug 2009 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 Kyle P. Larson, Laurent Godin, Raymond A. Price; Relationships between displacement and distortion in orogens: Linking the Himalayan foreland and hinterland in central Nepal. GSA Bulletin 2010;; 122 (7-8): 1116–1134. doi: https://doi.org/10.1130/B30073.1 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 Greater Himalayan sequence rocks exposed in the Manaslu–Himal Chuli Himalaya can be separated into distinct upper and lower parts. Deformation recorded in both parts occurred at temperatures ranging between ∼450 °C and ∼640 °C and is characterized by almost equal coaxial and noncoaxial components. Across the upper Greater Himalayan sequence, peak metamorphic temperatures are essentially isothermal, whereas corresponding metamorphic pressure estimates across the same section decrease downward with an apparent gradient of 620 bars/km. In the lower Greater Himalayan sequence, however, both metamorphic pressure and temperature decrease with structural depth. The abnormal pressure gradient in the upper Greater Himalayan sequence is attributed to ∼50% vertical thinning during southward displacement, while the inverted gradient in the lower portion is interpreted to be the result of coeval exhumation and downward expansion of the Main Central thrust shear zone and the progressive incorporation of more rock into the Greater Himalayan sequence. Deformation in the upper portion of the Greater Himalayan sequence was characterized by extending flow, i.e., extension in the direction of flow, whereas deformation in its lower portion was characterized by compressing flow, i.e., compression in the direction of flow. Extending flow is a distinctive feature of displacement and distortion in deep orogenic hinterlands, while compressing flow is emblematic of displacement and distortion in orogenic foreland regions. The transition between the upper and lower parts of the Greater Himalayan sequence therefore represents a fundamental transition between hinterland-style deformation, involving processes such as lateral midcrustal flow, and foreland-style deformation, involving critical-taper thrust-fold wedge development. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.