HR: 16:56h
AN: V14A-05    [Abstracts]
TI: Tracing The Boundary Between UHP And HP Metamorphic Belts In The Southwestern Sulu Terrane, Eastern China: Evidence From Mineral Inclusions In Zircons Of Metamorphic Rocks
AU: Liu, F
EM: liufulai@ccsd.org.cn
AF: Insitute of Geology, Chinese Academy of Geological Sciences, No.26 Baiwanzhuang Road, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China, Beijing, 100037 China
AU: * Xu, Z
EM: xzq@ccsd.org.cn
AF: Insitute of Geology, Chinese Academy of Geological Sciences, No.26 Baiwanzhuang Road, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China, Beijing, 100037 China
AU: Liou, J
EM: Liou@pangea.stanford.edu
AF: Deaprtment of Geological and Environmental Sciences, Stanford University, Department of Geological and Environmental Sciences, Stanford University, Stanford, CA94305, USA, San Franscisco, CA94305 United States
AB: The southwestern Sulu terrane, eastern China is divided into four fault-bounded lithological units. From northwest to southeast, they are orthogneiss unit, supracrustal rock unit, kyanite-bearing quartzite-marble unit and paragneiss-schist unit. Inclusions of index minerals in zircon separates from more than 90 samples from these units were identified using laser Raman spectroscopy and electron microprobe analysis. Coesite and coesite-bearing ultrahigh-pressure mineral assemblages occur in zircon separates from various amphibolite-facies metamorphic rocks in the orthogneiss and supracrustal rock units. Most coesite-bearing zircons contain the following UHP mineral assemblages: coesite + garnet + omphacite + phengite and coesite + garnet + jadeite + rutile + apatite in the paragneiss, coesite + kyanite + rutile + apatite in the kyanite-bearing quartzite, coesite + aragonite in the marble and coesite + phengite in the orthogneiss. Whereas aragonite- and phengite-bearing high-pressure mineral assemblages are preserved in zircons from many amphibolite- to greenschist-facies metamorphic rocks in kyanite-bearing quartzite-marble and paragneiss-schist units. The index HP mineral inclusion assemblages are characterized by aragonite + garnet + phengite + quartz and garnet + phengite + albite + quartz in the paragneiss, kyanite + phengite + quartz in the kyanite-bearing quartzite, aragonite + quartz in the marble, and phengite + quartz + apatite in the orthogneiss. The spatial distribution of the pressure and temperature estimates and recent surface mapping result constrain an exact boundary between UHP and HP belts in the southern Sulu terrane along a ductile shear zones in the Donghai region.
DE: 8102 Continental contractional orogenic belts
DE: 3660 Metamorphic petrology
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting