Contribution to the Holocene North Atlantic wind activity reconstruction from Lake Igaliku, South Greenland
Abstract
Lacustrine deposits from Lake Igaliku, South Greenland (N61°00’22”, W45°26’28”) were studied to investigate subarctic Holocene climate history. Analyses of the well dated sediment sequence (22 radiocarbone dates) used high-resolution grain size analysis, high-resolution geophysical (MSCL) and geochemical core scanning (XRF core scanner), X-ray radiography, ICP-MS geochemistry, DRX mineralogy and organic geochemistry. The 4 meters long sequence recovered from Lake Igaliku spans the entire lake history (last 10 000 years) following the last glaciation of the area, indicated by a succession from glaciolimnic to limnic sediment. The combination of the different proxies provides detailed information about the evolution of the lake system and documents changes in wind activity in South Greenland from 9500 BP to the present. The intermediate geographical setting of Lake Igaliku, between the Greenland ice sheet and the Atlantic Ocean, provides also a unique opportunity to link the lake-sediment record to ice core records, fjord shelf marine records and deep Atlantic marine records in the wider context of oceanic and atmospheric circulation above the North Atlantic region. Wind stress variability is documented by changes in detritic flux (reflected in MS and porosity), energy mobilized during sediment transport (grain size) and oxygenation of the bottom water of the lake (Mn/Fe ratio). The lake Igaliku record shows striking similarities with the GISP2 calcium record (insoluble continental dust). The sequence records well known windy events such as the 8200BP, 5500BP and the Little Ice Age, and also presents concomitant variations with the GISP2 Ca record at secular-to-decadal time scales. This study demonstrates that changes in wind strength above the North Atlantic region can influence long distance dust transport, recorded at the hemispheric level in the GISP2 Ca record, as well as local sediment transport within a lake catchment area.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMPP11F..02M
- Keywords:
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- 0305 ATMOSPHERIC COMPOSITION AND STRUCTURE / Aerosols and particles