Full vector paleosecular variation (PSV) recorded on the Koolau Volcano, Oahu, Hawaii during the Matuyama Chron at Makapuu Point (ca. 2.6 to ~2.2 Ma).

夏威夷欧胡岛库劳火山在马卡普点松山纪元期间（约 2.6 至约 2.2 Ma）记录的全矢量古世变 (PSV)。

• 批准号: 1620594
• 负责人: Emilio Herrero-Bervera
• 金额: $ 16.55万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1620594&HistoricalAwards=false
• 关键词: Full; vector; paleosecular; variation; PSV

Paleomagnetic (i.e. fossil magnetism) data are the unique source of observations to understand the geomagnetic transitions and hence the geodynamo processes involved in field generation. Due to the fact that there is a need to obtain reversal records from volcanic sequences in order to have a better understanding of the generation of the Earth's magnetic field, it is proposed to study a long sequence (about ~191 meters) of lavas from the island Oahu, Hawaii at a site known as Makapuu Point, Koolau Volcano with the main objective of investigating the full range of paleomagnetic signals recorded before during and after several successive polarity transitions. The section covering ~410,000 years of field changes includes the possibility of studying the detailed recording of the successive magnetic field reversals such as the Gauss-Matuyama, Cryptochron C2r.2r-1 and the onset of the Reunion Subchron, since the base of the section is 2.60+/-0.13 million years old, the middle part is 2.49+/-0.07 million years old and about 10 m below the top of the section the age is ~2.19+/-0.12 million years old. The objectives of this 2 year research study are related to the knowledge of field variations during periods like reversals and excursions and related to the critical time intervals that precede and follow reversals that so far have only been documented from a few sedimentary sequences, for the interval between 2.6 to ~2.012 Ma. Reversal studies cannot be separated from the surrounding polarity intervals and most records published so far were not long enough to provide complete information. The sequence offers the exceptional opportunity to study changes over a time period that includes several polarity intervals and thus documents the paleofield behavior over various time constants. This is a basic condition to extract and bring up significant constraints for the theoretical and numerical modeling of the generation of the paleofield. This research will have impacts on field like magnetostatigraphy, rock magnetism, geomagnetism and physical volcanism. Several undergraduate students will be supported and involved in all aspects of the research.The proposal is focused on full vector studies in order to determine the total field vector and Paleosecular Variation (PSV) of the "stable" polarities. The study will focus on the successive periods of polarity and their associated reversals. The paleointensity experiments will be conducted using a version of the Thellier-Coe as well as the differential pTRM "multi-specimen" methods. The PIs have imposed severe criteria to discard samples affected by magneto-mineralogical transformations and with magnetization components involving multi-domain grains. It is important to deal with paleointensity values that rely on a minimum number of 5 to 8 determinations per flow in order to perform suitable statistical treatment. Given the time consuming aspect of paleointensity studies, a two-year period is envisaged to achieve the goals of this proposal including 10 more radiometric 40Ar/39Ar age determinations. The principal investigator and four undergraduate students will carry out the entire research project. The involvement of undergraduate students will be a priority in this project, from fieldwork, laboratory work, analysis and publication of the results. Data will be disseminated through publication and on the web and community maintained paleomagnetic and geochronologic databases. This project will provide the stimulus to maintain the paleomagnetics operation at UH and the Rare Gas Lab. at the Univ. of Wisconsin at Madison both of which are used by a diverse group of students and researchers from all over the world.

古磁（即化石磁性）数据是了解地磁转变的独特来源，因此是田间产生所涉及的Geodynamo过程。 Due to the fact that there is a need to obtain reversal records from volcanic sequences in order to have a better understanding of the generation of the Earth's magnetic field, it is proposed to study a long sequence (about ~191 meters) of lavas from the island Oahu, Hawaii at a site known as Makapuu Point, Koolau Volcano with the main objective of investigating the full range of paleomagnetic signals recorded before during and after several successive polarity过渡。 The section covering ~410,000 years of field changes includes the possibility of studying the detailed recording of the successive magnetic field reversals such as the Gauss-Matuyama, Cryptochron C2r.2r-1 and the onset of the Reunion Subchron, since the base of the section is 2.60+/-0.13 million years old, the middle part is 2.49+/-0.07 million years old and about 10 m below the top of the section the age is 〜2.19 +/-有9.2万年的历史。这项两年研究的目标与逆转和偏移等期间的现场变化知识有关，以及与之前的关键时间间隔相关，这些时间间隔仅记录在少数沉积序列中，以2.6至〜2.012 ma之间的间隔。逆转研究不能与周围的极性间隔分开，到目前为止，大多数发布的记录还不足以提供完整的信息。该序列为研究一个时间段的变化提供了出色的机会，其中包括几个极性间隔，因此记录了各个时间常数的古场行为。这是提取和产生对古菲尔德产生的理论和数值建模的重要约束的基本条件。这项研究将对诸如Magnetostatatraphy，Rock磁性，地磁和物理火山的田地产生影响。 将支持几名本科生，并参与研究的各个方面。该建议集中于全面的矢量研究，以确定“稳定”极性的总田间矢量和古生物变异（PSV）。该研究将重点关注极性的连续时期及其相关的逆转。 Paleistensenty实验将使用Thellier-CoE的版本以及差分PTRM“多特定”方法进行。 PI已施加了严重的标准，以丢弃受磁性矿物学转化影响的样品，并具有涉及多域晶粒的磁化成分。重要的是要处理依赖每流量最少5到8个测定数量以执行适当统计处理的紫色值。鉴于普雷强度研究的耗时，设想了两年的时间，以实现该提案的目标，包括10次辐射40AR/39AR年龄确定。首席研究员和四名本科生将执行整个研究项目。本科生的参与将是该项目的优先事项，从现场工作，实验室工作，分析和结果发布。 数据将通过出版物以及网络和社区传播，并维护古磁和地质数据库。该项目将提供刺激，以维持UH和稀有气体实验室的古磁性操作。在大学。威斯康星州的麦迪逊郡（Wisconsin）都由来自世界各地的一群学生和研究人员使用。