Collaborative Research: RUI--Late Holocene Climate of the Central Andes Identified from Sedimentary, Stable Isotopic, Geochemical and Biological Proxies

该项目旨在从安第斯山脉中部跨越南纬11度至南纬20度的一系列湖泊中获得高分辨率的古气候记录，并将以该地区湖泊的最高时间分辨率（基于先前工作的5至20年）记录气候变化。由此产生的时空数据集将提供有关该地区干旱频率、强度和空间变异性的信息，该地区有数百万人生活在维持生计的水平上，水资源有限，冰川迅速退缩，目前在冬季旱季提供重要的水源。从每个湖泊的沉积中心恢复的沉积物岩心将被用来记录水文状态随时间的变化，通过测量介形虫壳或自生碳酸盐（如果有）或沉积物纤维素（基岩地质不允许在沉积物中保存自生碳酸钙）的氧和碳同位素比率。这些分析将与从浅水到深水的核心样带研究相结合，以确定和确定湖泊水位的大规模变化。结果将通过稳定同位素质量平衡和水文状况的建模研究进行量化。这项工作产生的结果将与环太平洋地区的其他古记录一起进行研究，以确定造成观测到的变化的可能的气候机制。特别是，结果将与厄尔尼诺/南方涛动（ENSO）和太平洋年代际涛动（PDO）的长期记录进行比较。预计这些资料将有助于预测、准备和规划未来的干旱。

This project is designed to obtain high-resolution paleoclimate records from a series of lakes in the central Andes spanning latitudes 11 degrees south to 20 degrees south, and will document climatic variability at the highest possible temporal-resolution (5 to 20 years based on previous work) from lakes in this region. The resulting spatial-temporal dataset will provide information regarding drought frequency, intensity and spatial variability across a region where millions of people live at a subsistence level, limited water-resources, and rapidly retreating glaciers that currently supply an important source of water during the winter dry season.Sediment cores recovered from the center of deposition in of each lake will be used to document changes in the hydrologic status through time by measuring oxygen and carbon isotopic ratios on either ostracod shells or authigenic carbonate (where available), or sediment cellulose where the bedrock geology does not allow for the preservation of authigenic calcium carbonate in the sediments. These analyses will be augmented with core transect studies from shallow to deep water to identify and date large-scale variations in lake level. Results will be quantified using modeling studies of stable isotope mass balance and hydrologic status. The results arising from this work will be studied alongside other paleorecords from the Pacific Rim to identify the likely climatic mechanism(s) responsible for the observed changes. In particular, results will be compared with long records of the El Nino/Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). This information is expected to be helpful for forecasting, preparing and planning for future droughts.