An Integrated Study of Paleointensity during Mesozoic and Tertiary using Dated Basalt, Submarine Basaltic Glass, and Single Plagioclase Crystals

利用定年玄武岩、海底玄武岩玻璃和单斜长石晶体对中生代和第三纪古强度进行综合研究

• 批准号: 0207389
• 负责人: Xixi Zhao
• 金额: $ 27.71万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0207389&HistoricalAwards=false
• 关键词: Integrated; Study; Paleointensity; during; Mesozoic

ZhaoEAR-0207389The record of the intensity of Earth's magnetic field during the past (paleointensity) carries important information about the geodynamo and probably about the state of Earth's interior that is not contained in the record of paleodirection. Firm conclusions regarding long-term paleointensity variation and its role in mantle dynamics require averages of many more data than are currently available. For this reason, the investigators propose to carry out new determinations of Earth's field during Mesozoic and Tertiary time using dated rock materials from Siberia, Kazakhstan, China, the Faroe Islands, and Ontong Java and Kerguelen plateaus. The principal objectives of this study are focused on three important geophysical problems which are currently debated: (1) to obtain reliable paleointensities to test the hypothesis that there was an extended period of low field intensity in the Mesozoic and, if so, to better define its onset and termination; (2) to determine mid-Cretaceous paleointensities to test the recent suggestion that the field strength was unusually high during the Cretaceous Normal Superchron (CNS); and (3) to obtain mean paleointensity values during the Tertiary period of high reversal frequency for comparison with those for the mid-Cretaceous period of low reversal frequency to see whether there is a correlation between reversal rate and geomagnetic field strength. The rock units the investigators have targeted for sampling and those they currently have available have high potential of providing valuable paleointensity data to address these questions of fundamental importance in geophysics. The opportunity to compare paleointensity results from these different geologic materials is a strong secondary motivation for this research.

Zhaoear-0207389过去（Paleistentie）在地球磁场强度的记录中，带有有关Geodynamo的重要信息，并且可能涉及地球记录中未包含的地球内部状态。关于长期古显着变化及其在地幔动力学中的作用的牢固结论需要比目前可用的更多数据。因此，调查人员建议使用来自西伯利亚，哈萨克斯坦，中国，法罗群岛以及安大爪哇省和凯格伦高原的过时的岩石材料在中生代和第三纪期间对地球领域进行新的决定。这项研究的主要目标集中在目前辩论的三个重要的地球物理问题上：（1）获得可靠的古敏性，以检验中生代中长期存在低场强度的假设，并更好地定义其发病和终止和终止； （2）确定白垩纪中期敏感性，以测试最近的建议，即在白垩纪正常超静脉（CNS）期间，田间强度异常高； （3）在高逆转频率的第三纪期间获得平均古显着值，以与低反转频率的白垩纪中期相比，以查看逆转速率与地磁场强度之间是否存在相关性。调查人员针对采样的岩石单位，目前拥有的岩石单位具有很高的潜力，可以提供有价值的古生物数据，以解决这些在地球物理学中至关重要的问题。比较这些不同地质材料的古显着结果的机会是这项研究的强大次要动机。