Collaborative Research: A Deep-AUV Magnetic and Seismic Study of the Hawaiian Jurassic Crust - The Global Significance of Jurassic Magnetic Anomalies

为一项为期两年的研究提供资金，最初涉及为期 42 天的巡航，使用 AUV 从夏威夷线状侏罗纪磁静区 (JMQZ) 收集两个高分辨率地震剖面和近底部磁场数据。 PI 计划使用便携式多道地震系统和声纳浮标获得 800 公里长的磁力剖面以及局部地震反射和折射数据。地震数据将使他们能够评估侏罗纪地壳是否受到后来的板内白垩纪火山活动的影响。该磁数据将与之前研究的日本线序 JMQZ 数据进行比较。后者揭示了快速反转和场强下降，以及一段短波长和低振幅的明显不相干异常的时期。如果是真实且全局的（与局部不良信号相反），那么这个低振幅区域代表了地球磁场历史中非常不寻常的场行为。来自夏威夷的新数据及其与日本结果的比较将有助于检验这一假设，即这种不寻常的磁场行为确实是全球性的，这对地球深处的动力学以及构建中侏罗世时期强大的地磁极性时间尺度具有重要意义。更广泛的影响包括发现，同时促进研究生和本科生的海上教学和培训。还计划通过互联网和 WHOI 展览进行公众宣传。这些科学结果可能对地球动力学、磁场行为和地磁极性时间尺度产生深远的影响，并且对该领域的其他工作人员有用。

Funds are provided for a two-year study, initially involving a 42-day cruise to collect two high-resolution seismic profiles and near-bottom magnetic field data from the Hawaiian Lineation Jurassic Magnetic Quiet Zone (JMQZ) using an AUV. The PIs plan to obtain 800 km long magnetic profiles as well as local seismic reflection and refraction data using a portable multichannel seismic system and sonobuoys. Seismic data will allow them to evaluate whether the Jurassic crust has been affected by later intra-plate Cretaceous volcanism. This magnetic data will be compared to the previously studied JMQZ data from the Japanese Lineation. The latter reveals rapid reversal and decreasing field intensity as well as a period of apparently incoherent anomalies with short wave lengths and low amplitudes. If real and global (as opposed to a local bad signal) this low amplitude zone represents an very unusual field behavior in Earth?s magnetic field history. The new data from Hawaii and its comparison with Japanese results will allow testing the hypothesis that this unusual field behavior was indeed global, which has important implications for dynamics of the deep Earth and for the construction of a robust geomagnetic polarity time scale for the Mid-Jurassic period.Broader impacts include discovery while promoting teaching and training at sea for graduate and undergraduate students. Public outreach is also planned through internet and WHOI exhibits. The scientific results could have far reaching implications for Earth dynamics, magnetic field behavior and geomagnetic polarity time scale and useful to other workers in the field.