Fluid-absent and fluid-fluxed melting of muscovite in metasedimentary sources are two types of crustal anatexis to produce the Himalaya Cenozoic leucogranites.Apatite grains separated from melts derived from the two t...Fluid-absent and fluid-fluxed melting of muscovite in metasedimentary sources are two types of crustal anatexis to produce the Himalaya Cenozoic leucogranites.Apatite grains separated from melts derived from the two types of parting melting have different geochemical compositions.The leucogranites derived from fluid-fluxed melting have relict apatite grains and magmatic crystallized apatite grains,by contrast,there are only crystallized apatite grains in the leucogranites derived from fluid-absent melting.Moreover,apatite grains crystallized from fluid-fluxed melting of muscovite contain higher Sr,but lower Th and LREE than those from fluid-absent melting of muscovite,which could be controlled by the distribution of partitioning coefficient(D_(Ap/Melt))between apatite and leucogranite.D_(Ap/Melt) in granites derived from fluidabsent melting is higher than those from fluid-fluxed melting.So,not only SiO_(2) and A/CNK,but also types of crustal anatexis are sensitive to trace element partition coefficients for apatite.In addition,due to being not susceptible to alteration,apatite has a high potential to yield information about petrogenetic processes that are invisible at the whole-rock scale and thus is a useful tool as a petrogenetic indicator.展开更多
基金supported by National Natural Science Foundation of China(41873023,41425010 and 92055202)The Second Tibetan Plateau Scientific Expedition and Research program(2019QZKK070203)+1 种基金National Key Research and Development Project of China(2016YFC0600304)China Geological Survey(DD20190057).
文摘Fluid-absent and fluid-fluxed melting of muscovite in metasedimentary sources are two types of crustal anatexis to produce the Himalaya Cenozoic leucogranites.Apatite grains separated from melts derived from the two types of parting melting have different geochemical compositions.The leucogranites derived from fluid-fluxed melting have relict apatite grains and magmatic crystallized apatite grains,by contrast,there are only crystallized apatite grains in the leucogranites derived from fluid-absent melting.Moreover,apatite grains crystallized from fluid-fluxed melting of muscovite contain higher Sr,but lower Th and LREE than those from fluid-absent melting of muscovite,which could be controlled by the distribution of partitioning coefficient(D_(Ap/Melt))between apatite and leucogranite.D_(Ap/Melt) in granites derived from fluidabsent melting is higher than those from fluid-fluxed melting.So,not only SiO_(2) and A/CNK,but also types of crustal anatexis are sensitive to trace element partition coefficients for apatite.In addition,due to being not susceptible to alteration,apatite has a high potential to yield information about petrogenetic processes that are invisible at the whole-rock scale and thus is a useful tool as a petrogenetic indicator.
