Centenial-Scale Climate Variability During the Early Deglaciation (19 to 16 ka) Expressed in Speleothem Oxygen Isotopes From the Yucatan Peninsula, Mexico
Abstract
Speleothems were sampled from multiple caves in Yucatan, Mexico. U/Th ages indicate growth of the stalagmites during the Last Glacial Maximum (LGM) chronozone and into the early deglaciation (~21 to 16 ka). Oxygen and carbon isotopes were measured on calcite samples drilled every 0.5mm along the growth axis of the speleothems. Oxygen isotope values are greatest during the LGM chronozone with a sharp decrease in values at 19 ka. The early deglaciation (19 to 16 ka) is marked by centennial-scale changes in δ18O that are superimposed upon a gradual increase to 16 ka where growth stopped. Centennial- scale variability during this period is similarly expressed in percent reflectance records from the Cariaco Basin, (Peterson et al., 2000), suggesting a regionally coherent pattern of climate change. The δ18O of speleothem calcite during the LGM-to-early deglacial period reflects changes in cave temperature and the δ18O of precipitation. To better understand the controls on the δ18O of precipitation in northern Yucatan we are collecting rainfall samples for δ18O analysis along with temperature and precipitation data. Initial results over a 2.5 year period suggest a correlation between δ18O and rainfall amount.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMPP11C1402G
- Keywords:
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- 1637 Regional climate change;
- 4958 Speleothems