Sedimentary characteristics and evolution of Ediacaran glaciation in western Henan Province, southern North China Craton

Abstract

The Ediacaran-Cambrian transition is recognized as a warm period. However, glaciations have been reported in many paleocontinents worldwide during this transition, including the Luoquan glaciation in Northern China. The type of glacier remains unclear, and there are still uncertainties regarding the differences and similarities between the Luoquan glaciation and other Ediacaran glaciations, which restrict global comparison of glaciation characteristics. Research on sedimentary characteristics and succession of eight sections of the Luoquan and Dongpo formations in western Henan Province in the southern North China Craton shows that from north to south, the Luoquan and Dongpo formations show three vertical facies associations spatially, indicating an obvious sedimentary environment evolution of subglacial-periglacial-glaciomarine-shallow marine, namely, from the subglacial lodgement to the periglacial outwash fan and permafrost, then to the proximal glaciomarine grounding-line fan and iceberg rainout to the distal glaciomarine ice-rafted deposits, and finally to the normal shallow sea.The spatial evolution of sedimentary environment indicates that the Luoquan glaciation in western Henan Province was a large ice sheet that extended from land to the sea and was not completely frozen but partially melted during warm periods, and temporary open-water conditions existed. Further comparison shows that although the number, frequency and global characteristics have not yet been determined, the global Ediacaran glaciations also show dynamic evolution characteristics from continental to marine glaciers, which is similar to the evolution mechanism of ice sheet during the snowball Earth, and also not indicative of hard snowball Earth pattern of complete ice cover.