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Metamorphic Characteristics and Tectonic Implications of the Kadui Blueschist in the Central Yarlung Zangbo Suture Zone, Southern Tibet
- Source :
- Journal of Earth Science. 29:1026-1039
- Publication Year :
- 2018
- Publisher :
- Springer Science and Business Media LLC, 2018.
-
Abstract
- The Kadui blueschist is located in the central section of Yarlung Zangbo suture zone (YZSZ), southern Tibet, and has been subjected to the subduction of the Neo-Tethyan Ocean below the Asian Plate and provides important clues for better understanding the evolution of the India-Asia convergence zone. In this paper, the systematical petrographic and mineral chemical studies were carried out on the Kadui blueschist, which reveal a mineral assemblage of sodic amphibole, chlorite, epidote, albite and quartz with accessory minerals of titanite, calcite and zircon. Electron microprobe analyses demonstrate that amphibole shows zoned from actinolite core to ferrowinchite/riebeckite rim composition indicating that the sodic amphibole has formed during a prograde metamorphic event. The protolith of the blueschist is an intermediate-basic pyroclastic rock. The calculated pseudosection indicates a clockwise P-T path and constrains peak metamorphic conditions of about 5.9 kbar at 345 °C. This condition is transitional between pumpellyite-actinolite, greenschist and blueschist facies with a burial depth of 20–22 km and a thermal gradient of 15–16 °C/km. This thermal gradient belongs to high pressure intermediate P/T facies series and is possibly related to a warm subduction setting of young oceanic slabs. Our new findings indicate that the Kadui blueschist in the central part of YZSZ experienced a rapid subduction and exhumation process as a response to a northward subduction of the Neo-Tethyan oceanic lithosphere during the initial India-Asia collision stage.
- Subjects :
- Blueschist
010504 meteorology & atmospheric sciences
Subduction
Greenschist
Metamorphic rock
Geochemistry
Metamorphism
engineering.material
010502 geochemistry & geophysics
01 natural sciences
Actinolite
engineering
General Earth and Planetary Sciences
Protolith
Geology
Amphibole
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 1867111X and 1674487X
- Volume :
- 29
- Database :
- OpenAIRE
- Journal :
- Journal of Earth Science
- Accession number :
- edsair.doi...........432515509c06e1696b6df3af8b06e738
- Full Text :
- https://doi.org/10.1007/s12583-018-0854-9