Abstract
The basic granulite, which is considered to be the MORB based on geochemistry and isotopic characteristics[1], has been discovered recently as the enclaves in the Yingjiang islandarc magmatic suite on the border of Burma and west Yunnan, east of Myitkyina suture in the eastern Burma. The laser micro-area40Ar-39Ar technique is used to date the age of garnet and cliopyroxene that is the result of the early metamorphic event. The isochron outcome is ∼74.4 Ma which is induced to be the age of the suduction event of the Myitkyina oceanic crust on the basis of the Cenozoic lithosphere tectonic evolution, tectonic thermal events and the age of deformation and metamorphism. The discovery of the high-grade or high-pressure metamophic rocks in the island-arc magmatic suite by the way of studying itsP-T-t paths can provide a good way to study the age and process of oceanic crust subduction, slab break-off, metamorphic terrain exhumation and the evolution of paleoocean basin.
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Zhong, D., Ji, J. & Hu, S. Subduction age of Neo-Tethys oceanic crust in southwest Yunnan, China: Laser micro-area40Ar-39Ar dating. Chin. Sci. Bull. 44, 2196–2199 (1999). https://doi.org/10.1007/BF03182708
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DOI: https://doi.org/10.1007/BF03182708