Geochemical Insights from Clinopyroxene Phenocrysts into the Magma Evolution of an Alkaline Magmatic System from the Sanshui Basin, South China

The Sanshui Basin is located at the northern continental margin of South China Sea and characterized by a rift basin. bimodal volcanic rocks in record early Cenozoic magmatic activity Block, but evolution that produced poorly understood. Clinopyroxenes provide an opportunity to investigate magma during ascent. In this work, we classified nine types clinopyroxene phenocrysts according composition texture cogenetic basalt-trachyandesite-comenditic trachyte, while unzoned have sequence diopside-hedenbergite-aegirine along with increase trace element contents decrease Mg#, indicating genesis was dominated fractional crystallization closed system. However, clinopyroxenes reversed zoning multiple process mixing recharge open While dominant process, mixing, recharge, crystal settling were also found influence evolution. Thermobarometric calculations showed crystallized several structural levels crust study, established plumbing system provides new constraints for Basin.