Petrologic case for Eocene slab breakoff during the Indo-Asian collision

Research Article| July 01, 2002 Petrologic case for Eocene slab breakoff during the Indo-Asian collision Matthew J. Kohn; Matthew J. Kohn 1Department of Geological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA Search for other works by this author on: GSW Google Scholar Christopher D. Parkinson Christopher D. Parkinson 1Department of Geological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Matthew J. Kohn 1Department of Geological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA Christopher D. Parkinson 1Department of Geological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA Publisher: Geological Society of America Received: 07 Dec 2001 Revision Received: 05 Mar 2002 Accepted: 19 Mar 2002 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2002) 30 (7): 591–594. https://doi.org/10.1130/0091-7613(2002)030<0591:PCFESB>2.0.CO;2 Article history Received: 07 Dec 2001 Revision Received: 05 Mar 2002 Accepted: 19 Mar 2002 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 Matthew J. Kohn, Christopher D. Parkinson; Petrologic case for Eocene slab breakoff during the Indo-Asian collision. Geology 2002;; 30 (7): 591–594. doi: https://doi.org/10.1130/0091-7613(2002)030<0591:PCFESB>2.0.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 The Greater Himalayan Sequence is the metamorphic core of the Himalaya and has been a focus of considerable study, yet its petrologic evolution remains controversial. Pre-Oligocene metamorphism was nearly obliterated by Miocene metamorphism and melting, which many workers ascribe to shear heating, unusually high concentrations of radioactive elements accompanying burial, and/or several kilometers of Miocene exhumation due to extensional faulting. Sparse Oligocene to Eocene ages are often assigned to a tectonically unspecified event. An alternative slab-breakoff model (subduction of Greater Himalayan rocks to ∼100 km depth in the Eocene followed by buoyant extrusion due to decoupling of the oceanic lithosphere) has also been proposed based on rare Eocene eclogites, but without explanation of Miocene melting or metamorphic petrogenesis. We argue that slab breakoff readily explains the Eocene eclogites, Miocene partial melts, and late Eocene K-rich magmas in southeastern Tibet, and that metamorphic and plutonic ages help define the timing and rates of breakoff and extrusion. This model implies that (1) much of the Greater Himalayan Sequence was subducted to depths greater than commonly considered, (2) fluid-absent, decompression melting at 30–35 km depth was the consequence of as much as 100 km of extrusion, rather than radioactive heating or a smaller, crustal level extensional or erosional event, and (3) eruption of Eocene, K-rich Tibetan Plateau lavas has no implication for topography of the Tibetan Plateau. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.