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).对从拉巴斯盆地（La Paz Basin）745米深度提取的岩芯样品的纹层沉积物开展地球化学与孢粉学分析，揭示了距今约4487年至260年期间降雨与海洋生产力的百年尺度变化。通过X射线荧光分析获取了古气候代用指标钛（Ti）、铁（Fe，代表陆源输入）以及钼（Mo，代表缺氧环境）的浓度，并利用库仑法二氧化碳分析仪测定了总有机碳浓度（total organic carbon, TOC，代表初级生产力）。海洋甲藻（dinoflagellates）与陆相孢粉形态物（pollen and spores，即花粉与孢子）的浓度可用于反演海洋生产力（primary productivity, PP）与降雨（RF）的变化，且地球化学分析结果与部分同源样品的孢粉学数据存在显著统计相关性与良好的图形拟合度。总有机碳浓度与异养甲藻（heterotrophic dinoflagellates）、桡足类（copepods）的浓度呈高度统计相关，而与陆相孢粉形态物仅呈中等相关，表明海洋初级生产力占据主导地位且随时间呈上升趋势。海洋生产力代用指标的数值可划分为四个演化阶段：整体呈现从低到高的变化趋势，并在900-290 BP期间达到峰值。钛与铁的浓度在统计与图形层面均与孢子及自养甲藻（autotrophic dinoflagellates）显著相关，证实其可作为降雨的可靠代用指标。降雨参数的数值相对稳定，可划分为四个具有差异的数值区间，整体同样呈现从低到高的变化，并在1050-600 BP期间达到峰值。上述代用指标可用于识别区域气候事件，如北美西南部记录的极端干旱期（1280-1070 BP），或是全球气候事件如中世纪暖期（Medieval Warm Period，1078-706 BP）与小冰期（Little Ice Age，706-260 BP）。