Large areal extent of ultrahigh-pressure metamorphism in the Sulu ultrahigh-pressure terrane of East China: new implications from coesite and omphacite inclusions in zircon of granitic gneiss

Coesite and omphacite inclusions have been identified for the first time as minute inclusions in zircon from amphibolite-facies granitic orthogneiss i n the Sulu ultrahigh-pressure (UHP) metamorphic terrane of eastern China by Raman spectroscopy and microprobe analyses. The occurrences of these miner als in the voluminous granitic gneiss of Sulu support a regional and pervas ive UHP metamorphic event that predated regional amphibolitic retrogression . Taking into account the widespread discoveries of coesite in other lithol ogies, we thus conclude that a substantial crustal component in the Sulu UH P metamorphic terrane appears to have shared a common history of Triassic s ubduction to mantle depths and later exhumation. (C) 2000 Elsevier Science B.V. All rights reserved.