Discovery of the Huronian Glaciation Event in China: Evidence from glacigenic diamictites in the Hutuo Group in Wutai Shan

Abstract

Paleoproterozoic glacigenic diamictites have provided key evidence for the Great Oxidation Event (GOE) at ∼2.3 Ga associated with the widespread Huronian Glaciation Event (HGE). Here we report for the first time Paleoproterozoic glacigenic diamictite from the Sijizhuang Formation of the Hutuo Group in Wutai Shan, China formed during the late stage of HGE.The Sijizhuang Formation comprises diamictite, sandstone and siltstone-mudstone facies, conforming to a glaciomarine association. The diamictites show weak sorting and roundness, and carry a few striated and faceted boulders. Typical dropstones and associated structures are present in the sandstone and siltstone-mudstone facies. Diamictite facies, which characterizes the lower portion of the Sijizhuang Formation, displays an upward decrease, with a concomitant increase in the proportions of sandstone and siltstone-mudstone facies. The lithofacies associations of diamictite with sandstone and siltstone-mudstone indicate a frequently changing hydrodynamic environment. The petrochemical compositions of different lithofacies show that the clasts were multi-sourced and generated by limited weathering, in keeping with a cold climate.Available isotope age data constrain the glacigenic deposition of the Sijizhuang Formation to between 2.40 and 2.13 Ga, and most likely from 2.2 to 2.1 Ga. This estimate compares well with the 2.4–2.1 Ga age of the widespread HGE but the Sijizhuang diamictite appears to be younger than the last glacial unit (Gowganda Formation) in the type area of the HGE in Canada and suggests a locally protracted glacial event.