T130 Geochemical and Mineralogical Records from Ancient Lake Sediments

Tuesday, 29 October 2002
8:00 AM - 12:00 PM

THE USE OF REGRESSION MODELS TO CALCULATE WATER TEMPERATURE FROM THE MG/CA RATIOS OF OSTRACODE VALVES IN LAGUNA BABÍCORA, CHIHUAHUA, MEXICO

Paper number: T130-5
Program: Technical Sessions
Time: 9:00 AM – 9:15 AM

Authors

Abstract

Laboratory and field experiments on two species of continental water ostracodes yielded constants and coefficients to reconstruct water temperature. Limnocythere staplini and Cypridopsis vidua were used for the laboratory and field experiments, respectively. The regression model coefficients have been applied to a number of lakes in western North America (Mexico and USA). Here, we document our recent results on applying the regression model coefficients for L. staplini to organisms of the genus Limnocythere (L. ceriotuberosa and L. platyforma) from Laguna Babícora.

Shell Mg/Ca ratios of 204 specimens of these two species were used to estimate water temperature. Our data show that paleowater temperature ranged from 5.6 to 21.3°C (with 2s values ranging from 0.2-4.8°C), suggesting a close correlation with atmospheric temperatures around the lake. The temperatures recorded are in good agreement with a modern mean winter (3.5°C) and mean summer (20°C) temperatures obtained from the area between 1970 and 1980.