Late Pleistocene C4 plant dominance and summer rainfall in the southwestern United States from isotopic study of herbivore teeth

Connin, S. L.; Betancourt, J.; Quade, J.

Abstract:

Patterns of climate and C4 plant abundance in the southwestern United States during the last glaciation were evaluated from isotopic study of herbivore tooth enamel. Enamel ??13C values revealed a substantial eastward increase in C4 plant consumption for Mammuthus spp., Bison spp., Equus spp., and Camelops spp. The ??13C values were greatest in Bison spp. (-6.9 to + 1.7???) and Mammuthus spp. (-9.0 to +0.3???), and in some locales indicated C4-dominated grazing. The ??13C values of Antilocaprids were lowest among taxa (-12.5 to -7.9???) and indicated C3 feeding at all sites. On the basis of modern correlations between climate and C4 grass abundance, the enamel data imply significant summer rain in parts of southern Arizona and New Mexico throughout the last glaciation. Enamel ??18O values range from +19.0 to +31.0??? and generally increase to the east. This pattern could point to a tropical or subtropical source of summer rainfall. At a synoptic scale, the isotope data indicate that interactions of seasonal moisture, temperature, and lowered atmospheric pCO2 determined glacial-age C4 abundance patterns.

Genre:

Article

ProdID:

70020678

Citation Author:

Connin, S. L.; Betancourt, J.; Quade, J.

Citation Contributing Office:

Citation Datum:

Citation Day:

Citation Edition:

Citation Editor:

Citation End Page:

193

Citation Issue:

Citation Keywords:

Citation Language:

English

Citation Larger Work Title:

Quaternary Research

Citation LatN:

Citation LatS:

Citation LonE:

Citation LonW:

Citation Month:

Citation No Pagination:

Citation Number Of Pages:

Citation Online Only Flag:

Citation Phsyical Description:

Citation Projection:

Citation Public Comments:

Citation Publisher:

Citation Series:

Citation Series Code:

Citation Series Number:

Citation Search Results Text:

Late Pleistocene C4 plant dominance and summer rainfall in the southwestern United States from isotopic study of herbivore teeth; 1998; Article; Journal; Quaternary Research; Connin, S. L.; Betancourt, J.; Quade, J.