Time-Dependent Soil Morphologies and Pedogenic Processes on Raised Beaches, Broggerhalvoya, Spitsbergen, Svalbard Archipelago

Abstract

A complex sequence of raised beaches on Broggerhalvoya, western Spitsbergen, was subdivided into a tripartite age series based on elevation, degree of geomorphic preservation, radiocarbon dates, and molluscan amino acid ratios. The uppermost beach deposit from 55 to 80 m asl [above sea level] was deposited during the episode C interval (130-290 ka [1000 yr]). The intermediate beach series from 44-55 m asl formed during the last 12 ka (episode A). Soils on the beach crests exhibit stages of silt accumulation that range from coatings on clast surfaces to complete infilling of voids in the primary beach sediment. The letter l to be used in conjunction with master soil horizon notation to indicate the presence of silt accumulations is proposed. Carbonate coatings (stages I and II) occur on clast bottoms within but more commonly below the zone of maximum silt accumulation. Soils on the episode A surface exhibit a 15- to 35-cm-thick Bl horizon with stage II carbonate occurring to 15-40 cm depth. Soils on the intermediate surface contain a 40- to 60-cm-thick Bl horizon with stage II carbonate extending to 40- to 75-cm depth. Soils of episode C age have Bl horizons that are 70-105 cm thick and stage II carbonate to depths below 80 cm. Selective dissolution, frost and hydration shattering, translocation of released fines, and precipitation of carbonate are the dominant processes operating in these soils.