Triassic continental subduction in central Tibet and Mediterranean-style closure of the Paleo-Tethys Ocean
Abstract
The Qiangtang metamorphic belt (QMB) in central Tibet is oneof the largest and most recently documented high-pressure (HP)to near-ultrahigh-pressure (near-UHP) belts on Earth. Lu-Hfages of eclogite- and blueschist-facies rocks within the QMBare 244-223 Ma, indistinguishable from the age of UHPmetamorphism in the Qinling-Dabie orogen. Results of a U-Pbdetrital zircon study suggest that protoliths of the QMB includeupper Paleozoic Qiangtang continental margin strata and sandstonesthat were derived from a Paleozoic arc terrane that developedwithin the Paleo-Tethys Ocean to the north. We attribute QMBHP metamorphism to continental collision between the Qiangtangterrane and a Paleo-Tethys arc terrane. This collision, andthe coeval South China-North China collision, may haveslowed convergence between Laurasia and Gondwana-derived terranesand initiated Mediterranean-style rollback and backarc basindevelopment within much of the remnant Paleo-Tethys Ocean realm.
- Publication:
-
Geology
- Pub Date:
- May 2008
- DOI:
- 10.1130/G24435A.1
- Bibcode:
- 2008Geo....36..351P