Multi-proxy Organic Geochemical Reconstruction of Holocene Hydroclimate Near the Western Greenland Ice Sheet Margin
Abstract
Anthropogenic warming is projected to drive profound change to the Arctic hydrological cycle within the century, most notably in the intensification of rainfall, with potential feedbacks to the climate system and cryosphere. However, the relationship between hydroclimate and cryosphere variability is poorly constrained in the long-term due to a scarcity of high-resolution hydroclimate records from the Arctic. We analyze the stable hydrogen isotopes (dD) of leaf wax biomarkers from lacustrine sediments spanning the Holocene to 9000 cal. year B.P. from Lake Gus (67.032ºN, 52.427ºW, 300 m a.s.l.; informal name), a small lake approximately 90 km from the modern western margin of the Greenland Ice Sheet. We interpret the signal of aquatic leaf wax isotopes in the context of a survey of 100 modern lake water samples from western Greenland across an aridity gradient to better understand the combined climatological and hydrological controls on lake water dD in the study area. We compare variability of aquatic and terrestrial leaf wax isotopes to infer changes in relative moisture throughout the Holocene, and complement our leaf wax record with analysis of glycerol dialkyl glycerol tetraethers (GDGTs) and alkenones, to produce records of summer temperature. Pairing temperature and leaf wax isotope records provides a means to constrain the changing dD-temperature relationship throughout the Holocene and infer moisture source variability. In combination, these proxies produce a comprehensive hydroclimate record at approximately centennial scale to evaluate shifts in relative moisture, temperature, and moisture source, and to investigate the interaction between hydroclimate and Greenland Ice Sheet margin fluctuations through the Holocene.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.B33A2075C
- Keywords:
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- 0424 Biosignatures and proxies;
- BIOGEOSCIENCES;
- 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCES;
- 1055 Organic and biogenic geochemistry;
- GEOCHEMISTRY;
- 4912 Biogeochemical cycles;
- processes;
- and modeling;
- PALEOCEANOGRAPHY