Holocene climatic variability : glacial history from an Arctic fjord and shelf, western Spitsbergen, Svalbard

KEYWORDS: Svalbard, glacial, fjord, Holocene, climate General circulation models predict that climatic warming will initially be manifest in a decrease in ice volume at high latitudes and a corresponding rise in global sea level. This study has been prompted by two factors: (i) the recognition of rapid climate change and the concern of the magnitude of its progress; (ii) instrumental records of climatic variation exceed a century, rarely two centuries, yet are temporally too short and spatially incomplete to reveal the full range of seasonal to millennial-scale variability. A transect of sediment cores were collected from the basins of glaciated Kongsfjorden on the northwestern coast of Svalbard. The cores were investigated for lithology, grain size, ice rafted debris, organic carbon, foraminifera, and stable isotopes in foraminiferal tests. Age control was provided by seven AMS radiocarbon ages combined with core top 210Pb chronology. The recovered sedimentary sections span a range of ages, reaching a maximum of ca.6000 years. The proxy records reveal variations in sedimentary processes, bioproductivity, glacier front position, sea ice conditions, and the hydrographic regime in the fjord. These characteristics are interpreted in terms of regional and global climate changes during the mid and late Holocene. The records reveal warm stable conditions for three millennia subsequent to 6000 yrs BP. Initial Neoglacial cooling occurred between 3000 and 2000 yrs BP followed by intervals of ameloriated marine conditions between 1300 and 900 and between 500 and 280 yrs BP, briefly interrupting the decreasing trend in productivity that culminated in the Little Ice Age.