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.
