Holocene marine terraces of Kunashiri Island, Kurile Islands

Abstract

Low marine terrace sequence of Kunashiri Island includes Atlantic, Subboreal and Subatlantic terraces, reflecting sea level oscillations during Middle-Late Holocene. The section of Atlantic terraces exposes storm ridge deposits, covered lacustric silts and peat. A minor regression took place during Atlantic-Subboreal cooling. Subboreal deposits record two high sea level positions at about 4010-3400 yr BP and 2950-2620 yr BP. Small estuarine lagoons and inlets developed in that time. The cooling and ocean level lowering at Subboreal-Subatlantic boundary was accompanied by the formation of dune fields, and swamping of the lagoon coasts (2220±80 yr BP, 1440±60 yr BP, GIN-7895, GIN-7262). A subatlantic terrace (2.5 m) formed during ocean level rise to 1 m about 1170-820 yr BP. Dunes were formed during the Little Ice Age. -from Authors