Paleomagnetic Assisted Chronology of IODP Sites U1395 and U1396

该提案旨在利用IODP exp. 340期间在Monserrat近海钻探的岩心，为1395和1396地点开发古地磁年代学。岩心为半深海沉积物，夹层有灰岩和浊积岩。岩心提供了连续的沉积和火山活动记录，1395点1.1 m (9 cm/kyear)， 1396点4.5 m （3 cm/kyear）。记录优于现存的陆地和海洋记录。两个岩心都记录了地磁倒转；1395年4次，1396年17次。用于研究的u通道样品已到手，存放在俄勒冈街4oC的地核（伪单畴铁磁颗粒）的磁性是理想的。用于记录磁场行为和古强度。拟开展的工作包括：制定详细的磁年表。反卷积测量，进行高精度测量，在反转间隔做高分辨率RPI。在同一岩心上进行O同位素和Ar-Ar同位素的年代学研究。环境和地层学工作。利用火山和半深海沉积物的不同磁性来识别和记录火山层。火山灰年代学。试图确定火成岩的来源，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。将寻找撒哈拉沙尘。记录的长度为研究地磁场的行为提供了机会。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。样品将被逐步消磁，并在厘米尺度上测量NRM。质谱、ARM和IRM将用于鉴定磁性矿物。这些信息将用于开发RPI的代理。选定的样品将被分解，以确定磁性矿物的粒度性质，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助理和一名本科生，他们将接受古地磁数据测量、数据处理和解释方面的培训。完整的数据集将通过MAGIC数据库提供给研究界。

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.