Partial melting associations with metamorphic evolution, exhumation, and magmatism in convergent plate margins: Constraints from Silurian-Devonian HP pelitic gneiss and felsic vein in the Proto-tethys Altyn orogen

This dataset contains geochemical data and U-Pb Geochronolgy of Siluran-Devonian HP pelitic gneiss and felsic vein in the Proto-tethys Altyn orogen. We demonstrate partial melting via detailed analyses of petrology and geochemistry on HP pelitic gneiss, felsic veins and separated centimetric leucosomes. Felsic veins distributed along the foliation plane and deformed together with the HP pelitic gneiss, reserve irregular phengite, plagioclase and quartz with corrosion boundary, and are enriched in K, Al, Rb and lacked Ca, indicating that phengite dehydration melting has been responsible for the production of melt. The HP pelitic gneiss records P–T–t path of priority decompression–heating followed by clockwise decompression–cooling and preserves sparsely Alpine-type peak metamorphism and strong granulite-facies overprinting. Phase equilibrium modeling and zircon geochronology results reveal the partial melting caused by depressurization-heating during early exhumation (c.430–400 Ma) of HP pelitic gneiss. And the resulting melt gradually changed from sodium-rich to potassium-rich, which may explain the coexisting of sodic and potassic granitoids in active continental margins, and promote the geochemical evolution of continental crust toward more felsic compositions. Moreover, the partial melting of SMCA MP-HP rocks may supplementary explanation for the Late Siluran-Early Devonian magmatic thermal event in the region.