Paleomagnetic Assisted Chronology of IODP Sites U1395 and U1396

IODP 站点 U1395 和 U1396 的古地磁辅助年代学

• 批准号: 1260671
• 负责人: Robert Hatfield
• 金额: $ 18.97万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-05-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1260671&HistoricalAwards=false
• 关键词: Paleomagnetic; Assisted; Chronology; IODP; Sites

This proposal seeks to develop a paleomagnetic chronology for sites 1395 and 1396 using cores drilled offshore of Monserrat during IODP exp. 340. The cores are hemipelagic sediments intercalated with tephra/ash and turbidites. The cores provide a continuous record of sedimentation and volcanic activity, 1.1 MY for site 1395 (9 cm/kyear), 4.5 MY for site 1396 (3 cm/kyear). Records are superior to extant terrestrial and marine records. Both cores record magnetic reversals; 4 in 1395 and 17 in 1396. The U-channel samples for the study are in hand, stored at 4oC at Oregon St. The magnetic properties of core (pseudo-single domain ferromagnetic grains) are ?ideal? for recording magnetic field behavior and paleointensity. Proposed work includes:1.Develop a detailed magnetochronology. Deconvolute measurements, make high precision measurements, do high resolution RPI at reversal intervals. Chronology will be correlated with O isotope and Ar-Ar work on the same cores.2.Environmental and stratigraphic work. Use the differing magnetic properties of volcanic and hemipelagic sediments to identify and log tephra layers. Tephrochronology. Attempt to identify sources of tephra, e.g. different island volcanos have different lava compositions and magnetic properties. Relate magnetitc properties to grain size, weathering history etc.3.Other. Will look for Saharan dust. Length of record provides opportunity to examine behavior of geomagnetic field. The work will be accomplished by creation of a composite spliced record of 1395 and 1396 to aid in sample selection for U-channel work,. The samples will be progressively demagnetized and NRM measured at the cm scale. MS, ARM, and IRM will be used to identify magnetic minerals. This information will be used to develop a proxy for RPI. Selected samples will be disaggregated to determine particle size properties of the magnetic minerals and relate this to the environmental record.BROADER IMPACTS: This project will directly support a postdoctoral research associate at OSU and an undergraduate student who will be trained in measurement, data processing and interpretation of paleomagnetic data. The complete data set will be made available to the research community through the MAGIC database.

该提案旨在利用 IODP 实验期间在蒙塞拉特岛近海钻探的岩心，为 1395 和 1396 地点制定古地磁年表。 340. 岩心是夹有火山灰/灰和浊积岩的半远洋沉积物。岩心提供了沉积和火山活动的连续记录，1395 号地点为 1.1 MY（9 厘米/年），1396 号地点为 4.5 MY（3 厘米/年）。记录优于现有的陆地和海洋记录。两个磁芯都记录磁反转； 1395 年的 4 号和 1396 年的 17 号。用于研究的 U 通道样品已在手，储存在俄勒冈街 4oC 下。核心（伪单畴铁磁颗粒）的磁性是“理想的”吗？用于记录磁场行为和古强度。建议的工作包括：1.开发详细的磁年代学。对测量进行解卷积，进行高精度测量，以反转间隔进行高分辨率 RPI。年代学将与同一岩心上的O同位素和Ar-Ar工作相关联。2.环境和地层工作。利用火山和半远洋沉积物的不同磁性来识别和记录火山灰层。年代学。尝试确定火山灰的来源，例如不同的岛屿火山有不同的熔岩成分和磁性。将磁性能与晶粒尺寸、风化历史等联系起来。3.其他。将寻找撒哈拉尘埃。记录长度提供了检查地磁场行为的机会。这项工作将通过创建 1395 和 1396 的复合拼接记录来完成，以帮助 U 通道工作的样本选择。样品将被逐渐消磁并在厘米尺度上测量 NRM。 MS、ARM 和 IRM 将用于识别磁性矿物。该信息将用于开发 RPI 代理。选定的样品将被分解，以确定磁性矿物的粒度特性，并将其与环境记录联系起来。 更广泛的影响：该项目将直接支持俄勒冈州立大学的一名博士后研究员和一名本科生，他们将接受测量、数据处理和古地磁数据的解释。完整的数据集将通过 MAGIC 数据库提供给研究界。