Abrupt temperature and hydrologic changes during D-O and Heinrich Events at paleolake Les Echets, southeastern France
Abstract
Paleoenvironmental proxy data from sediments of paleolake Les Echets record abrupt changes in terrestrial and aquatic ecosystems during the last Glacial period, from 36 to 16 kyr BP. Synchronous fluctuations in lake level, aquatic primary productivity, terrestrial vegetation and runoff occurred, consistent with the pattern of D-O and Heinrich events in Greenland ice cores and North Atlantic marine records. Although these events appear broadly consistent, differences in detail between millennial-scale oscillations in Les Echets and Greenland records have been interpreted as evidence for asynchroneity between Greenland temperatures and European ecosystem changes. Here we present new molecular isotopic data from Les Echets sediments providing independent evidence for temperature and hydrologic change in southwestern Europe during this interval. Carbon isotopes in aquatic biomarkers confirm increased primary productivity in Les Echets coincident with D-O interstadials in Greenland. Differences between hydrogen isotopic values in aquatic and terrestrial biomarkers record dramatic shifts to more arid conditions during D-O stadials. Crenarcheal membrane lipid distributions reveal abrupt shifts in runoff and temperature that are consistent with the timing of D-O and Heinrich events. These data provide a climatic context for the environmental changes previously reconstructed in this region, and suggest that it may be possible to identify the presence of lags between local climate changes and ecosystem responses.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMPP41E..02H
- Keywords:
-
- 1041 Stable isotope geochemistry (0454;
- 4870);
- 1055 Organic and biogenic geochemistry;
- 1605 Abrupt/rapid climate change (4901;
- 8408);
- 1637 Regional climate change;
- 3305 Climate change and variability (1616;
- 1635;
- 3309;
- 4215;
- 4513)