COLLABORATIVE RESEARCH: RUI: (GRGC) High Resolution Glacial Geologic and Palynologic Records of the Last Deglaciation in the Tropical Andes

该项目的主要目标是从热带安第斯山脉四个地区的湖泊沉积物岩心中获得冰川和植被变化的连续、高分辨率、AMS 14C数据代用记录，这些地区已经记录了末次冰期到间冰期过渡期间气候突变的证据。pi不仅力求改进热带安第斯山脉晚冰期气候振荡的年代学，而且还力求改进解释沉积学和孢粉学记录的基础。具体而言，pi建议：i)结合冰川地质学和冰川湖泊沉积学，估算末次消冰期间冰川平衡线高度变化的时间、速率和幅度；ii)结合现代植被研究和亚马孙盆地西部沉积物岩心的孢粉学分析，估算该地区末次冰川期向间冰期过渡期间植被突变的时间和古气候因素。iii)与厄瓜多尔地质学家合作，确定最后一次消冰期间沉积的地球化学上明显的温层单元的年代和特征，以便这些重要的等时线可以用来精确地关联保存在热带安第斯山脉不同地点的沉积物和冰芯中的古气候代用记录；iv)根据初步和已公布的放射性碳年龄，为特定的冰碛提供更接近的年龄限制；与YD和H1事件几乎同时沉积。

9418886 Rodbell The primary objective of the proposed project is to obtain continuous, high-resolution, AMS 14C datable proxy records of glaciation and vegetation change from lacustrine sediment cores that span the last deglaciation and Holocene from four regions in the tropical Andes where evidence for abrupt climatic reversals during the last glacial-to-interglacial transition have already been documented. The PIs seek to improve not only the chronology of late-glacial climatic oscillations in the tropical Andes but also to improve the basis for interpreting the sedimentologic and palynologic records. Specifically, the PIs propose: i) to couple glacial geology and glacial-lacustrine sedimentology to provide estimates for the timing , rate, and magnitude of changes in glacier equilibrium -line altitudes during the last deglaciation, ii) to couple modern vegetation studies with palynological analyses of sediment cores from the western Amazon Basin to estimate the timing of and paleoclimatic factors responsible for the abrupt changes in vegetation that marked the last glacial-to-interglacial transition in this region, iii) to collaborate with Ecuadorian geologists to date and characterize geochemically conspicuous tephra units that were deposited during the last deglaciation so that these important isochrons may be used to correlate precisely among proxy records of paleoclimate preserved in sediment and ice cores from different sites in the tropical Andes, and iv) to provide closer age constraints for specific moraines, which, based on both preliminary and published radiocarbon ages, were deposited at about the same time as the YD and H1 Events.