Petrogenesis of Natural Rocks

I've always been fascinated by the origin of different types of rocks on our Earth. For my master thesis, I worked on the petrogenesis of the A-type granite widely distributed in East Junggar area, NW China. Based on geochemistry, isotopic composition and geochronology of the A-type granite rock samples, we hypothesized that the A-type granite may be formed by the fractional crystallization of I-type granodioritic magma with plagioclase as the dominant differentiating mineral, since the granodioritic plutons are closely associated with the A-type granite both temporally and spatially. We then used high-pressure techniques (e.g., multi-anvil and piston cylinder) to experimentally simulate this fractional crystallization process. We investigated the crystallization behavior of plagioclase in a natural granodioritic melt, and combined with geochemical analysis on quenched samples and mass balance calculations, we demonstrated that fractional crystallization of I-type granodioritic melt at high pressure is indeed a feasible and important process in generating the A-type magmas in East Junggar.

Relevant Publications

Xu, M., & Tang, H. (2018). Plagioclase crystallisation in a granodioritic melt and its petrogenetic implications for the origin of the A-type granite in East Junggar, NW China. Geological Journal, 53(3), 929-946.

Xu, M., & Tang, H. (2016). Research progress in experimental study of the crystallization of plagioclase. Acta Mineralogica Sinica, 36(1), 61-69. (In Chinese with English abstract)