Data Chem Paly 4kyrs La Paz Basin_100-48 samples

Geochemical and palynological analyses of laminated sediments of samples corresponding to a core extracted at 745 m depth from La Paz Basin, allow recognition of centennial variations on rainfall and marine productivity from ~4487 to ~260 years BP. Concentrations of the paleoclimate proxies Ti and Fe (terrigenous input) and Mo (anoxia) were obtained by X-ray fluorescence analyses and total organic carbon concentrations (TOC, primary productivity) with a CO2 coulometer. Concentrations of marine (dinoflagellates) and continental palynomorphs (pollen and spores) indicate changes in marine productivity (PP) and rainfall (RF), with chemical results having significant statistical correlations and good graphic similarity with palynological data obtained from some of the same samples. Concentrations of TOC have a high statistical correlation with heterotrophic dinoflagellates and copepods, but only medium with continental palynomorphs, indicating the predominance of marine PP with an increasing trend through time. Values of proxies for PP differentiate four intervals: generally going from low to high, and reaching their highest values from 900-290 BP. Concentrations of Ti and Fe are statistically and graphically correlated with spores and autotrophic dinoflagellates, indicating their reliability as proxies for RF. Values of RF parameters are relatively stable, defining four intervals with differing values, mostly varying from low to high and reaching their highest values from 1050 to 600 BP. These proxies allow identification of regional conditions as an extreme drought period (1280-1070 BP) reported in southwestern North America, or global events like the Medieval Warm Period (1078-706 BP) and the Little Ice Age (706-260 BP).