When did the roof collapse? Late Miocene north-south extension in the high Himalaya revealed by Th-Pb monazite dating of the Khula Kangri granite

Abstract

Research Article| June 01, 1997 When did the roof collapse? Late Miocene north-south extension in the high Himalaya revealed by Th-Pb monazite dating of the Khula Kangri granite M. A. Edwards; M. A. Edwards 1Department of Geological Sciences, State University of New York, Albany, New York 12222 Search for other works by this author on: GSW Google Scholar T. M. Harrison T. M. Harrison 2Department of Earth and Space Sciences and Institute for Geophysics and Planetary Physics, University of California, Los Angeles, California 90024 Search for other works by this author on: GSW Google Scholar Geology (1997) 25 (6): 543–546. https://doi.org/10.1130/0091-7613(1997)025<0543:WDTRCL>2.3.CO;2 Article history first online: 02 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 M. A. Edwards, T. M. Harrison; When did the roof collapse? Late Miocene north-south extension in the high Himalaya revealed by Th-Pb monazite dating of the Khula Kangri granite. Geology 1997;; 25 (6): 543–546. doi: https://doi.org/10.1130/0091-7613(1997)025<0543:WDTRCL>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 SocietyGeology Search Advanced Search Abstract Th-Pb ion microprobe measurements made on 12 monazite grains from the Khula Kangri granite, Tibet-Bhutan frontier, are interpreted to indicate that crystallization occurred at 12.5 ± 0.4 Ma. The leucogranite is cut by the Gonto La detachment, part of the Southern Tibet detachment system that has allowed upper-level, north-directed extension of the Himalayan orogen. Significant orogen-normal extension in southern Tibet appears to have continued 8–10 m.y. later than previously recognized. This is the first reported crystallization age for a leucogranite east of the Yadong cross structure, an apparent 70 km offset of the high Himalaya and Southern Tibet detachment. West of the Yadong cross structure, reliable ages for high Himalaya events (major Main Central thrust slip, granite generation and emplacement, attainment of critical topography, and major detachment extension) group between ca. 24 and 19 Ma. We interpret the west-to-east change across the Yadong cross structure to be due to either (1) an abrupt, ∼10 m.y. younging of principal high Himalayan events or (2) a deeper (thus younger) exposed part of the footwall of the southern Tibet detachment. Near Khula Kangri, the Southern Tibet detachment is cut by the highly oblique Yadong-Gulu rift; a manifestation of Tibet plateau east-west extension. Integrated estimates of magnitude, and rate, of detachment displacement suggest that the observed postcrystallization north-directed extension lasted for 1–3 m.y., after which time the Yadong-Gulu rift formed. This interpretation is consistent with initiation of east-west extension of Tibet at ca. 8 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.