Seminar

We present a systematic dataset for the petrology, mineralogy, geochronology and geochemistry of the enclave-bearing calc-alkaline I-type granitoids from Chinese Altai, CAOB, with the aim to constrain the petrogenetic processes involved in the generation of the igneous suite. Geochemical data of the host granitoids suggest that their parental magma was formed by efficient mixing between an evolved residual mantle-derived magma and a continental-derived felsic magma in the deep crustal hot zone. Once generated and ascended into higher crustal level, the mafic magma intruded into and mechanically mingled with the incompletely crystallized granitoid magma to form the MME. Combined profiles on the morphology, chemical zonation and in-situ Sr-isotope of the plagioclase suggest two stages crystallization of the granitoid magma accompanied by decompression and degassing, during which process the mafic recharge in the magma chamber induced not only the changes in physical conditions but also local melt mixing in relation to chemical and isotopic exchange. An integrated pattern of the arc granitoids and associated MME formation is provided, with in-depth mixing of mafic and felsic magmas controlling the major compositions, while mingling and limited mixing during ascent and crystallization and late-stage alteration in higher crustal level finally determined the texture, mineral compositions and enclave morphology.