Speleothem Paleoclimatology of the Last Glacial Maximum and Deglaciation in Yucatan, Mexico
Abstract
Two speleothems were collected in August 2005 from Columnas Cave near Tzucacab, Yucatan, Mexico. Both stalagmites have basal ages placing the initial growth during the Last Glacial Maximum (LGM). The first sample, Hobo 3, has a basal U/Th age of 21,089 +/- 221 years and the second sample, Hobo 4, has a basal U/Th age of 21,823 +/- 261 years. Oxygen isotopes were measured on calcite samples drilled every 0.5mm along the growth axis of these speleothems. Oxygen isotope values are relatively low at the base of both Hobo 3 and 4 during the LGM, and increase during the period inferred to represent the Late Glacial. Lower oxygen isotopic values during the LGM suggest a cold, wet climate in Yucatan followed by more arid conditions during the Late Glacial. This interpretation is consistent with recent findings from sediment cores from Lake Peten Itza, Guatemala (Hodell et al., 2006). We speculate that a cold, wet LGM may have been caused by increased winter precipitation related to polar outbreaks and "Norte" winds, which bring rain to Yucatan today during the dry season. Arid conditions during the Late Glacial may coincide with delivery of glacial meltwater to the Gulf of Mexico via the Mississippi River. Although additional U/Th dates are needed to constrain the chronology, our preliminary results suggest that Hobo 3 and 4 stalagmites will provide a detailed history of climate change for the northern Yucatan Peninsula during the last glacial cycle.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMPP53A..08G
- Keywords:
-
- 1041 Stable isotope geochemistry (0454;
- 4870);
- 1637 Regional climate change;
- 3344 Paleoclimatology (0473;
- 4900);
- 4958 Speleothems