MESOZOIC VOLCANIC ROCKS IN JIANGXI

Jurassic-Cretaceous volcanic rocks in Jiangxi mostly occur as medium- and small-sized volcanic basins.The volcanic activity was obviously controlled by fractures.The volcanic rock associations and metallogenic specialization in southern Jiangxi are utterly different from those in northern Jiangxi as the conditions of the geological structures and behaviour of the magma source in both areas are different.In northern Jiangxi the andesite-dacite-rhyolite association is represented, showing features of reversed succession evolution;while in southern Jiangxi the basalt-dacite-rhyolite association is present, the Changpu cycle showing bimodal features. According to the characteristics of volcanic rocks, it is considered that this volcanic rock series was the product of subduction of the Pacific plate along the Benioff zone towards the Eurasian continent, belonging to active continentalmargin type. The magma was not derived from a single source. It might be derived from the mantle or originate in the continental crust （sial） by anatexis.