Publication Date:
2018-08-10
Description:
The Antarctic Circumpolar Current (ACC) plays an essential role in the thermohaline circulation
and global climate. Today, a large volume of ACC water passes through the Drake Passage, the
major geographic constrain for the circumpolar flow. Here we present the first millennial-scale
proxy records of Holocene and last glacial variations of the Drake Passage throughflow. Our study
reports geochemical, paleomagnetic, and grain-size data from a sediment core retrieved from the
upper continental slope off southernmost Chile. The site is located beneath the strong Cape Horn
Current that transports northern ACC water towards the Drake Passage. Our data reveal large
amplitude changes in current intensity proxy records suggesting pronounced variations in surface
and sub-surface flow. We interpret these changes in terms of strongly reduced contributions of
northern ACC water to the Drake Passage throughflow during the glacial in general and
particularly during millennial-scale cold phases as known from e.g. Antarctic ice-cores. At the
same time, advection of northern ACC water into the Humboldt current system was likely
enhanced. These results support climate models showing largely reduced volume transport
through the Drake Passage during the last glacial maximum and an increasing throughflow during
the last deglaciation that affected the strengthening of the Atlantic Meridional Overturning
Circulation.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Conference
,
notRev
Format:
application/pdf
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