Paleoweathering environments recorded in the Pliocene-Pleistocene Kobiwako Group, southwest Japan

Yoshida, Koki*; Hatano, Nozomi*; Sasao, Eiji   

Plio-Pleistocene sediment, distributed around southern part of Shiga prefecture and northern part of Mie prefecture, provides important paleoweathering records during Pliocene and Pleistocene periods. The authors estimated paleoweathering condition by means of geological and geochemical studies. The sediments derived from differentiated rock type display high weathering index showing the intense chemical weathering environments in hinterland. Meanwhile, the sediments supplied from not-differentiated rock type indicate the derivation under weak chemical weathering environments. The paleoweathering degree estimated with provenance analysis represents the reality of paleoweathering environments even in the sediments derived from mixed source rocks.