Ultrahigh-pressure garnet lherzolite from Chijiadian, Rongcheng County, in the Su-Lu region of eastern China |
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| Authors: | N Hiramatsu S Banno T Hirajima B Cong |
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| Institution: | Department of Geology and Mineralogy, Kyoto University, Kyoto, 606-01, Japan;Laboratory for Lithosphere Tectonic Evolution, Academia Sinica, Beijing 100029, China |
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| Abstract: | Abstract Petrological studies of a serpentinized garnet lherzolite body in Rongcheng of the Su-Lu region of eastern China revealed unusually high pressure. Spinel lherzolite probably in a subducting slab was transformed to garnet lherzolite at mantle depth. During exhumation, they were subsequently subjected to the granulite and then amphibolite overprinting and a phase of serpentinization. The peak P–T conditions of the garnet lherzolite estimated after detailed analysis of the metamorphic texture are 4–5 GPa and 820°C or 5–6 GPa and 780°C, depending on the chosen geothermobarometers. The lower dP/dT of the garnet lherzolite can be interpreted as the results of subduction of an old (say 100 Ma older than the time of collision) and cold, slab underneath the margin of the Sino–Korean craton. |
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| Keywords: | extremely low Al opx garnet lherzolite Rongcheng Su-Lu |
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