Geomorphic Development of the Chita Peninsula, Aichi Prefecture

Abstract

The Chita Peninsula, situated between the Mikawa Bay and the Ise Bay, is divided into following seven ladnform surfaces (recent alluvial plain is excluded). Morozaki (60-120m in altitude), Taketoyo (45-87m), Yokosuka (40-60m), Kamezaki (25-50m), Handa (10-30m), Iwaname (7-20m), and Ogawa (3-20m).Morozaki and Yokosuka surfaces are erosional surfaces of low relief, Taketoyo is a depositional surface formed as the fan-like flood plain, and others are coastal and river terraces. The author supposes that Morozaki surface was formed in earlier Pliocene, Ogawa surface was in Holocene, and others were in Pleistocene.Judging from the inclination of Morozaki surface and the crossprofile through land and sea-bottom, the southern part of the peninsula is a tilted block. From the distribution pattern and the undulatory deformation of Taketoyo surface, the central and northern part of this peninsula made the folded type movement with the axes of N-S direction.On the other hand, Taketoyo surface may be correlated to Yagoto surface in the Nobi plain and Miyoshi surface in the Nishi-Mikawa plain. From these affairs, the author also supposes that the Nobi plain had been connected with the Nishi-Mikawa plain through the Chita peninsula at the stage of Taketoyo surface formation. Kamezaki, Handa, Iwaname and Ogawa surfaces were formed during the stage of high sea level and the altitudes of estimated ancient shore-line are about 30-40m, 10-15m, 7-10m, and 5m.