Intracontinental Porphyry and Porphyry-Skarn Mineral Systems in Eastern China: Scrutiny of a Special Case “Made-in-China”
In this contribution we discuss a series of porphyry and porphyry-skarn mineral systems, which constitute important metallogenic belts along major lithospheric breaks and/or collision zones that form the margins of the North China craton and the Yangtze craton. We describe a selection of porphyry and porphyry-skarn deposits in the Great Xing’an Range in northeast China, the Yanshan-Liaoning, Xilamulum belts along the northern margin of the North China craton, the Qinling orogen, and the Middle-Lower Yangtze River Valley along the bonudaries between the North China and the Yangtze cratons. The occurrence of platform carbonate successions may have played some role in the evolution of ore fluids that resulted in the formation of porphyry-skarn deposits. The porphyry deposits of eastern China, although sharing some common features with classic porphyry systems that are related to convergent margins, do exhibit unusual features, particularly in terms of ore fluid compositions, the common presence of fluorite, hydrothermal alteration assemblages, which tend to be less hydrous than the porphyry at convergent margins. On the other hand, the porphyry mineral systems of eastern China have some similarities with the Climax-type porphyry. A major tectonothermal event (Yanshanian), which took place in the Jurassic-Cretaceous, affected eastern China and most of the eastern margin of Asia. This Yanshanian event was responsible for the magmatism and associated mineral systems in the region. The granitoid intrusions and accompanying porphyry and porphyry-skarn deposits were developed along orogenic belts and major structural discontinuities mostly along the tectonic boundaries between the North China and Yangtze cratons and between the northern margin of the North China craton and the Mongolia-Siberia plate. The porphyry and porphyry-skarn deposits herein described include: Chalukou in the Great Xing’an Range orogen, Jiguanshan in the Xilamulun metallogenic belt, Xiaojiayingzi, Lanjiagou, Chehugou, Yuanbaoshan in the Yanshan-Liaoning belt, Nanninhu, Yuchiling, Jinduicheng, Lemeingou in the East Qinling orogen, Tongchakoou, Shaxi from the Middle-Lower-Yangtze River Valley. The role of mantle-lithosphere dynamics in eastern China, which led to the formation of these porphyry and porphyry-skarn mineral systems, is discussed and reviewed.