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Tectonic evolution of the early Mesozoic blueschist-bearing Qiangtang metamorphic belt, central Tibet
dc.contributor.author | Kapp, Paul | |
dc.contributor.author | Yin, An | |
dc.contributor.author | Manning, Craig E. | |
dc.contributor.author | Harrison, T. Mark | |
dc.contributor.author | Taylor, Michael Halford | |
dc.contributor.author | Ding, Lin | |
dc.date.accessioned | 2015-03-18T19:46:20Z | |
dc.date.available | 2015-03-18T19:46:20Z | |
dc.date.issued | 2003-08-28 | |
dc.identifier.citation | Kapp, P., A. Yin, C. E. Manning, T. M. Harrison, M. H. Taylor, and L. Ding (2003), Tectonic evolution of the early Mesozoic blueschist-bearing Qiangtang metamorphic belt, central Tibet, Tectonics, 22, 1043, http://dx.doi.org/10.1029/2002TC001383, 4. | en_US |
dc.identifier.uri | http://hdl.handle.net/1808/17114 | |
dc.description | This is the published version. Copyright 2003 American Geophysical Union. All Rights Reserved. | en_US |
dc.description.abstract | A >500-km-long east-west trending metamorphic belt in the Qiangtang terrane of central Tibet consists of tectonic melange that occurs in the footwalls of Late Triassic–Early Jurassic domal low-angle normal faults. The melange is comprised of a strongly deformed matrix of metasedimentary and mafic schists that encloses lesser-deformed blocks of metabasites, Carboniferous–Triassic metasedimentary rocks, and early Paleozoic gneiss. Both the blocks and melange matrix exhibit greenschist, epidote-blueschist, and locally, epidote-amphibolite facies mineral assemblages. Thermobarometry reveals that the metamorphic belt experienced pressures of >10 kbar. Maximum equilibration temperatures for mafic schists in the melange matrix decrease from east to west, from ∼660°C near Shuang Hu (33°N, 89°E), ∼500°C near Rongma (33°N, 87°E), to ∼425°C near Gangma Co (34°N, 84°E). Equilibration at consistently high pressures over a large range of temperatures is compatible with metamorphism of Qiangtang melange within a low-angle subduction zone beneath a continental margin. Coupled structural, thermobarometric, and 40Ar/39Ar studies suggest that Qiangtang melange was exhumed in an intracontinental setting from depths of >35 km to upper crustal levels in <12 Myr by Late Triassic–Early Jurassic crustal-scale normal faulting. Detrital zircons from metasandstones within the melange matrix yield U-Pb ion-microprobe ages that range from early Paleozoic to Early Archean, and could have been sourced from terranes to the north of the Jinsha suture. Our results support a model in which Qiangtang melange was underthrust ∼200 km beneath the Qiangtang terrane during early Mesozoic flat-slab southward subduction of Paleo-Tethyan oceanic lithosphere along the Jinsha suture. This model predicts that significant portions of the central Tibetan continental mantle lithosphere were removed during early Mesozoic low-angle oceanic subduction and that the present-day central Tibetan deeper crust includes large volumes of underthrust early Mesozoic melange. | en_US |
dc.publisher | American Geophysical Union | en_US |
dc.subject | Tibet | en_US |
dc.subject | blueschrist | en_US |
dc.subject | melange | en_US |
dc.subject | exhumation | en_US |
dc.subject | subduction | en_US |
dc.subject | metamorphic core complex | en_US |
dc.title | Tectonic evolution of the early Mesozoic blueschist-bearing Qiangtang metamorphic belt, central Tibet | en_US |
dc.type | Article | |
kusw.kuauthor | Taylor, Michael Halford | |
kusw.kudepartment | Geology | en_US |
dc.identifier.doi | 10.1029/2002TC001383 | |
kusw.oaversion | Scholarly/refereed, publisher version | |
kusw.oapolicy | This item does not meet KU Open Access policy criteria. | |
dc.rights.accessrights | openAccess |