Partial Melting of Himalayan Orogen and Formation Mechanism of Leucogranites
Zhang Zeming
Kang Dongyan
Ding Huixia
Tian Zuolin
Dong Xin
Qin Shengkai
Mu Hongchen
Li Mengmei
Abstract：The core of the Himalayan orogen consists of high-grade metamorphic rocks and leucogranites,forming a natural laboratory for studying crustal anatexis and granite origin during the collisional orogeny.Based on recent achievements of the related studies,the condition,type and P-T path of metamorphism,and mechanism,degree and melt composition of anataxis as well as metamorphic and anatectic timing and duration of high-grade metamorphic rocks in the orogenic core are discussed in this paper.The obtained evidence shows that the orogenic core experienced high-pressure granulite-facies to eclogite-facies metamorphism,with a clockwise-type P-T path characterized by increasing temperature and pressure prograde and early retrogression of near-isothermal decompression,and that the high-pressure rocks record a prolonged high-temperature metamorphic and anatectic process.The muscovite-and biotite-dehydration melting of meta-pelitic rocks during the prograde metamorphism resulted in formation of melts with highly variable chemical compositions.In addition,the formation time and geochemical feature of the Himalayan leucogranites are also summarized.Finally,it is concluded that the leucogranites were derived from the dehydration melting of thickened lower crust during the collisional orogeny.
Keywords：high-temperature and high-pressure metamorphismpartial meltingtime and durationleucograniteHimalayan orogenpetrology
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：17( 82-98 )