The U.S. southwest has a limited water supply and is predicted to become drier in the 21st century. An improved understanding of factors controlling moisture sources and availability is aided by reconstruction of past responses to global climate change. New stable isotope and growth-rate records for a central Texas speleothem indicate a strong influence of Gulf of Mexico (GoM) moisture and increased precipitation from 15.5 to 13.5 ka, which includes the majority of the Bølling-Allerød warming (BA: 14.7-12.9 ka). Coeval speleothem records from 900 and 1200 km to the west allow reconstruction of regional moisture sources and atmospheric circulation. The combined isotope and growth-rate time series indicates 1) increased GoM moisture input during the majority of the BA, producing greater precipitation in Texas and New Mexico; and 2) a retreat of GoM moisture during Younger Dryas cooling (12.9-11.5 ka), reducing precipitation. These results portray how late-Pleistocene atmospheric circulation and moisture distribution in this region responded to global changes, providing information to improve models of future climate.
Bibliographical noteFunding Information:
This research was supported by NSF P2C2 award # AGS-0823665 to J. Banner and L. Yang, NSF Geobiology and Low Temperature Geochemistry award # EAR-1124514 to D. Breecker and J. Banner, and by the Geology Foundation , Jackson School of Geosciences Honors Program, and Environmental Science Institute of the University of Texas at Austin . We thank ownership and management of Cave Without a Name for access and logistical support, T. Quinn for access to stable isotope facilities, many students for assistance in the field and laboratory, discussions with N. Miller and A. Winter, and M. Cohen at NOAA's Air Resource Laboratory for help with processing of the HYSPLIT data. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
- Growth rate
- Stable isotope
- U.S. southwest