The Last Glacial aeolian record of the Island of Susak (Croatia) as seen from a high-resolution grain–size and rock magnetic analysis

Abstract

The loess-palaeosol record on the island of Susak in Croatia is a unique archive of Late Glacial climate changes in the Adriatic region, possibly even in the wider area. On Susak up to 90 m of thick Quaternary sediments were deposited, and are accessible for detailed palaeoclimate reconstructions. In this paper, the results of a high-resolution grain-size and rock magnetic investigation on the Last Glacial (Upper Pleniglacial) Sand Pit section from Susak are presented. In spite of its significant thickness, the Sand Pit section does not represent a continuous record; it is a result of a very dynamic environment. There, the deposition of dust and formation of loess has been interrupted by pedogenesis, periods of increased sand accumulation, erosion due to slope wash and water activity, redeposition and wildfires, and all in the time period of about 10.000 years of the Upper Pleniglacial, as seen from the IRSL dating results. The grain-size data clearly show a shift towards coarser grain sizes which differs from typical loess regions. Such predominance of the coarser-grained over the fine-grained fraction, very likely resulted from the predominance of deposition over pedogenesis, increased wind activity and proximal source of material. The rock magnetic signal preserved in the sediment also differs compared to loess-palaeosol records from other regions. The susceptibility values are several times higher than in the records from the Pannonian basin and from typical Eurasian loess. Both the increased susceptibility values and the grain-size are very likely the result of a significant proximal material input from the Po River plain.