Magnetic properties of Arctic sediments: implications for magnetic stratigraphy

北极沉积物的磁性：对磁性地层学的影响

• 批准号: 0806309
• 负责人: James Channell
• 金额: $ 10.39万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0806309&HistoricalAwards=false
• 关键词: Magnetic; properties; Arctic; sediments; implications

This project hypothesizes that zones of apparently reversed magnetization in Brunhes age sediments in the Arctic Ocean and Greenland-Norwegian Sea are due to self-reversal in the mineral greigite formed as alteration coatings from magnetite. Nine HOTRAX (Healy-Oden Trans-Arctic Expedition, 2005) cores will be studied in order to establish the stratigraphic control on natural remanent magnetization (NRM) component directions from core to core. Thermal demagnetization of NRM determined on Al foil-wrapped discrete sub-samples will help determine the carriers of NRM. Low temperature remanence loss and high temperature hysteresis data will establish the magnetic carriers. SEM (Scanning Electron Microscope) studies and X-ray diffraction of magnetic separates will augment the magnetic measurements. Successful completion of this project will identify a cause of reverse magnetization in Arctic marine sediments, leading to improved age dating of the sediments and correlations and control with global sediments based on magnetostratigraphy. The project will support one graduate student, and also involve undergraduate students in the core analysis.

该项目假设，在北冰洋和格陵兰-挪威海的Brunhes年龄沉积物中明显反向磁化的区域是由于磁铁矿蚀变涂层形成的矿物云英岩中的自反转。将对9个HOTRAX（Healy-Oden Trans-Arctic Expedition，2005）岩心进行研究，以确定地层对岩心之间自然反射磁化（NRM）分量方向的控制。在铝箔包裹的离散子样品上测定的NRM的热退磁将有助于确定NRM的载流子。低温剩磁损失和高温磁滞数据将确定磁性载体。磁性分离物的SEM（扫描电子显微镜）研究和X射线衍射将增强磁性测量。该项目的成功完成将确定北极海洋沉积物中反向磁化的原因，从而改进沉积物的年代测定，并根据磁性地层学与全球沉积物进行对比和控制。该项目将支持一名研究生，并让本科生参与岩心分析。