Geochemistry and Tectonics of the Xionger Group in the Eastern Qinling Mountains of China—a mid Proterozoic Volcanic arc Related to Plate Subduction

Abstract

Summary A mid Proterozoic volcanic series, the Xionger Group, in the eastern Qinling Mountains of central China, may be one of the earliest products of plate subduction in eastern Asia. The main rock types of the 1710 Ma Xionger Group are andesites and dacites of the calcalkaline series. The rocks of the Xionger Group have trace element contents and REE patterns which are comparable to those of lavas from modern active continental margins, implying that the Xionger Group volcanics had a similar tectonic setting. It appears that there was an important event in China at 1800–2000 Ma, after which plate tectonics with the Wilson cycle was the main contributor to crustal growth.