Storfjorden, Svalbard, is an area of intense brine formation. The brine is cold, dense, rich in oxygen
and CO2, and has reduced pH. Storfjorden is unique because it contains well-preserved agglutinated
foraminifera dating back to the beginning of the last deglaciation. We have investigated the distribution of
calcareous and agglutinated benthic foraminifera, benthic oxygen and carbon isotopes, calcium carbonate,
total organic carbon, and ice-rafted debris in five cores from Storfjorden comprising the Holocene and the
deglaciation. The purpose of the study is to reconstruct brine formation in the past under different climate
scenarios. The data indicate that in Storfjorden the ratio of agglutinated to calcareous benthic foraminifera
can be taken as a measure of the strength of brine formation. The foraminiferal data, which are supported by
stable isotopes, degree of fragmentation, and geochemical parameters, signify that brine formation intensified
during cold periods and weakened during warm periods. During the deglaciation, increased brine flow
coincides with the Older Dryas, the Intra-Allerød Cold Period, and the Younger Dryas. Brine formation increased
from circa 8200 years B.P. reaching periodic maxima during the last 4000 years B.P. in response to the unstable
climate. Maximum brine production correlates with the Dark Ages Cold Period circa 1500–1100 years B.P.
and the Little Ice Age circa 600–100 years B.P. Lower production correlates with the Roman Warm Period circa
2500–2000 years B.P. and the Medieval Warm Period circa 1000–700 years B.P
