Geochemitry of the Xiong’er volcanic rocks: implications for the Paleo-Mesoproterozoic accretion of the North China Craton

Abstract

The Xiong.er volcanic belt along the southern margin of the North China Craton is dominated by basaltic andesite and andesite with minor dacite and rhyolite. Geochemically, the Xiong.er volcanic rocks fall in the calc-alkaline series, with enrichments in the LILE and LREE, and negative anomalies on Nb-Ta-Ti, similar to arc-related volcanic rocks (He et al. 2008; Zhao et al. 2009). Available SHRIMP and LA-ICP-MS U-Pb zircon age data indicate that the volcanism forming the Xiong.er volcanic rocks erupted intermittently over a protracted interval from 1.78 Ga, through 1.76-1.75 Ga and 1.65 Ga, to 1.45 Ga, though a major phase of the volcanism occurred at 1.78-175 Ga (He et al. 2009). Taken together, the Xiong.er volcanic belt was most likely a Paleo-Mesoproterozoic continental magmatic arc at the southern margin of the North China Craton. Age-similar continental magmatic arcs were also present at the southeastern margin of Laurentia, southern margin of Baltica, northwestern margin of Amonzonia, and southern and eastern margins of the North Australia Craton, which are considered to represent subduction-related outbuilding on the continental margins of the supercontinent Columbia (Zhao et al. 2004).