Paleomagnetism of Glacial Diamictons and Subglacially Deformed Sediment

冰川多聚体和冰下变形沉积物的古地磁学

• 批准号: 8816097
• 负责人: John Ridge
• 金额: $ 5万
• 依托单位: Tufts University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-05-01 至 1991-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8816097&HistoricalAwards=false
• 关键词: Paleomagnetism; Glacial; Diamictons; Subglacially; Deformed

Remanent magnetization directions in glacial diamictons have not been tested against established records of the geomagnetic field at the time and place of deposition and the accuracies of diamictons as geomagnetic field recorders have not been determined. An established record of Late Wisconsinan geomagnetic declination, from DRM in varved sediment in the western Mohawk Valley, New York, will be used to test the fidelity of remanence from contemporaneous till, sediment flow deposits, pelagic rainout diamicton, and subglacially deformed lacustrine beds. In addition to remanence, anisotropy of magnetic susceptibility (AMS) and anisotropy of anhysteretic susceptibility (AAS) will be measured. AMS will be used to determine fabrics dominated by coarse particles that carry a viscous remanence, while AAS should record fabrics dominated by fine particles that carry a stable remanence. Petrographic analysis of microfabrics, AMS, and AAS will be used to determine whether remanence directions and particle alignment in various types of diamictons are related to geomagnetic field orientation, mass movement, subglacial shearing, dewatering or compaction. Unlike previous works, this study will: 1) test remanence direction against an established geomagnetic field record, 2) distinguish between genetic diamicton types, and 3) use AAS and petrofabric analysis to study grain alignment.

冰川杂岩的剩余磁化方向 没有根据既定的记录进行测试， 在沉积的时间和地点的地磁场和 地磁场记录仪的精度 确定了 一个建立的记录后期威斯康星州 地磁衰减，从DRM在纹状沉积物中， 纽约的莫霍克谷西部将被用来测试 同时期冰碛物、沉积物流的剩磁保真度 沉积物、远洋雨蚀杂岩和冰下变形 湖相床 除了剩磁， 磁化率（AMS）和各向异性的无滞后 将测量敏感性（AAS）。 AMS将用于 确定由粗颗粒为主的织物， 粘性剩磁，而AAS应记录织物为主， 携带稳定剩磁的细小颗粒。 岩相 微组构分析、AMS和AAS将用于确定 是否剩磁方向和粒子排列在各种 双光子的类型与地磁场方向有关， 块体运动、冰下剪切、脱水或压实。 不同于以往的工作，本研究将：1）测试剩磁 与已建立的地磁场记录相反的方向，2） 区分遗传性杂合子类型，和3）使用AAS和 岩石组构分析，以研究颗粒排列。