Melt inclusion evidence for limestone assimilation, calc-silicate melts, and “magmatic skarn”

Abstract Chemical exchange between silicate magmas and carbonate rocks has major implications for igneous fractionation, atmospheric CO2 flux, formation of mineral deposits. However, this process is only partly understood, long-standing questions whether, where, how can be digested by melts remain controversial. We describe evidence pervasive chemical melt rock in a shallow porphyry setting driven limestone assimilation. Melt inclusions endoskarn from the Chating Cu-Au deposit eastern China reveal that calc-silicate assemblage (diopside + andradite ± wollastonite epidote) was molten at time skarn coexisted with vapor as well sulfate- chloride-salt melts. Hence, we argue formed crystallization an immiscible produced assimilation rock, aided presence sulfate other fluxes, which turn promoted desilication intruding magma drove vigorous release.