Coesite inclusions in zircon from the country-rock orthogneiss of the southern Dabie ultrahigh-pressure terrane, central China were identified by Raman spectroscopy and electron microprobe microanalysis. All the coesite-bearing samples analyzed show amphibolite-facies mineral assemblages in the matrix, indicating that these gneissic rocks experienced ultrahigh-pressure metamorphism and then retrogression. Quartz inclusions are also present in the same samples, but some of them are accompanied by fractures and/or fluid inclusion arrays. Coesitebearing orthogneisses occur far from previously recognized UHP eclogites, indicating that coesite-bearing lithologies occur all over the southern Dabie unit, requiring subduction of the whole area to mantle depths.
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- Tracing the Extent of a UHP Metamorphic Terrane: Mineral-Inclusion Study of Zircons in Gneisses from the Dabie Shan
Juhn G. Liou
- Springer Netherlands
- Chapter 10