Hydrological responses of the Chihuahua Desert of Mexico to possible Heinrich Stadials.

Hydrological response of the Chihuahua Desert of Mexico to six different Heinrich Stadials (H6 to H1) is inferred with element ratio, carbonate abundance, and oxygen and carbon isotope compositions of lacustrine calcite in sediments collected from the Santiaguillo Basin. Overall runoff and hence precipitation remained below average during H6, H4, H2 and H1, and above average during H5 and H3. Similarly, runoff of H4 showed the least variability and it was most variable during H5. In general, dissolved HCO 3 − was dominantly sourced from atmospheric CO 2 during the intervals of less runoff. However, lacustrine productivity as well as atmospheric CO 2 influenced carbon isotope composition of dissolved HCO 3 − during the regimes of fluctuating hydrological conditions. H2 was an interval of relatively warmer water column and enhanced lacustrine productivity. Comparison with other records indicates occurrence of similar millennial-scale hydrological variability in the southwest US. However, we did not always observe concurrency in proxy records from the Chihuahua Desert of Mexico and southwest US. Similarity in tendencies of runoff into the Santiaguillo Basin and δ 18 O of speleothem from the Hulu Cave during the six different Heinrich Stadials suggests a possible hemispheric link between hydroclimate of the Chihuahua Desert of Mexico and the East Asian Monsoon. [ABSTRACT FROM AUTHOR]