Reconstruction of the marine paleoenvironment and paleoecology of the middle Holocene in the Oslo fjord area

Abstract

A warm phase has previously been observed in the early to middle Holocene geological record of the Northern hemisphere. Holocene invertebrate faunas in the Oslo fjord, Norway, are here studied in order to investigate their response to a changing climate. Studying ecological changes during this Holocene Thermal Maximum can help predicting the impact of present and future anthropogenic warming. Previous research around the Oslo fjord stated molluscs indicate a warm signal during deposition of the Tapes banks in the middle Holocene. Five beds are radiocarbon dated, placing the Upper Tapes banks between 7,800 and 5,000 cal yr BP. The faunal composition of the Upper Tapes banks has been studied, and compared with other Holocene deposits. Some interesting changes in faunal composition are observed, but no clear sign of a thermal maximum is found. Most species occurring in the Atlantic stage still live in the area nowadays, although a few of them decreased in abundance.