(ESH) Holocene Climatic Variations in the Midcontinent of North America: Analyses of Annually Laminated Sediments from Minnesota Lakes

湖泊的年积层沉积物（纹管）提供了一个独特的工具，以获得大陆古气候数据与安全的年表。 该建议旨在分析来自明尼苏达州四个湖泊的一套地球化学，沉积学和生物学代理的varved沉积物，以评估北美大陆中部的全新世气候变化。 这些指标包括纹层厚度、有机碳和无机碳、碎屑矿物、矿物组成、粒度、碳酸盐和介形虫壳的氧和碳同位素、介形虫壳的微量元素组成和花粉。 研究目标是：（1）利用近百年来的仪器气象资料，对纹层沉积物中的各种气候代用指标进行校准，以评估每个代用指标与气候因子的关系。（2）根据校准结果，通过解释我们研究地点的代用指标记录，评估全新世气候变化，特别是周期性和突变性变化，（3）将新的纹状沉积物数据与邻近地区其他高分辨率古气候研究的结果结合起来，提供全新世气候变化的区域综合，（4）比较北美大陆中部与格陵兰、北大西洋和地球仪其他地区的气候波动模式，以评估全新世气候变化的机制。

Annually laminated sediments (varves) from lakes provide a unique vehicle to acquire continental paleoclimatic data with secure chronologies. This proposal seeks to analyze varved sediments from four Minnesota lakes for a suite of geochemical, sedimentological, and biological proxies to assess Holocene climatic variability in the midcontinent of North America. These proxies include varve thickness, organic and inorganic carbon, detrital minerals, mineralogical composition, grain size, oxygen and carbon isotopes of carbonates and ostracode shells, trace-element composition of ostracode shells, and pollen. The research objectives are: (1) Calibrate various climatic proxies in varved sediments with instrumental weather data for the last 100 years to evaluate how each proxy is related to climatic factors, (2) Assess Holocene climatic variations, particularly cyclic and abrupt changes, by interpreting proxy records from our study sites on the basis of calibration results, (3) Integrate new varved-sediment data with findings from other high-resolution paleoclimatic studies in adjacent areas to provide a regional synthesis of Holocene climatic variations, (4) Compare patterns of climatic fluctuations in the midcontinent of North America with those in Greenland, the North Atlantic, and other parts of the globe to evaluate mechanisms of Holocene climatic variability.