Determining the Cause of a Magnetic Mineral-Paleorainfall Correlation in Recent Lake Sediments

确定近期湖泊沉积物中磁性矿物与古降雨相关性的原因

• 批准号: 0000948
• 负责人: Kenneth Kodama
• 金额: $ 13.38万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0000948&HistoricalAwards=false
• 关键词: Determining; Cause; Magnetic; Mineral; Paleorainfall

This is a proposal to investigate the mechanism causing a correlation observed between magnetic mineral concentration and paleorainfall variations in recent lake sediments from northeastern Pennsylvania. We propose to study the recent sediments from two different small glacial lakes, one dominated by sediment from allochthonous sources (Lake Waynewood) and one dominated by authigenic sources (Lake Ely), so a general model of the relationship between rainfall and mineral magnetism can be developed. Freeze cores will be collected at several locations in each lake. Mineral magnetic parameters (c, SIRM, ARM, ARM/SIRM, SIRM/c, HIRM) will be measured to magnetically characterize the lake sediments. Elemental analyses will be conducted to determine the importance of erosion (Na, Mg, K) or the possibility of reduction diagenesis (S, Mn, Fe). Electron microscopic (SEM, TEM) examination of magnetic extracts will look for magnetosotnes and evidence of dissolution due to reduction diagenesis. EDS will be used to determine if authigenic, ferromagnetic iron sulfides have been created. High resolution (1 mm) magnetic scanning of the cores with an FIT scanning magnetometer will allow a more detailed look at the SIRM variations and extension of the record into the low sedimentation rate, pre-settlement horizons.

这是研究引起磁性矿物质浓度与宾夕法尼亚州东北部沉积物的磁性矿物质浓度和古河降落变化之间相关性的机制的提议。我们建议研究来自两个不同的小冰川湖的最新沉积物，一个是由异物源（湖Waynewood）的沉积物主导的，一个由身份源（Ely湖）主导的沉积物，因此可以发展出降雨和矿物质磁磁性之间关系的一般模型。冻结核心将在每个湖泊的多个位置收集。将测量矿物磁参数（C，SIRM，ARM/SIRM，SIRM/C，HIRM），以磁性地表征湖泊沉积物。将进行元素分析以确定侵蚀的重要性（Na，Mg，K）或减少成岩作用的可能性（S，MN，FE）。电子显微镜（SEM，TEM）对磁提取物的检查将寻找磁磁体和由于减少成岩作用而导致的溶解证据。 EDS将用于确定是否已经创建了身份精元的铁磁铁。具有拟合扫描磁力计对芯的高分辨率（1毫米）磁扫描将使记录的变化和延伸到低沉积速率，预分解范围。