JQZ-Phoenix-MCS

This project examines a poorly understood period of geomagnetic field history, the Jurassic Quiet Zone, during which geomagnetic field strength appears to be much less than normal and the reversal rate much higher than normal. Changes in geomagnetic field behavior are thought to have geodynamic significance, such as indicating heat flux to the mantle from the core, affecting mantle convection. Moreover, the geomagnetic polarity timescale is used as a basis for magnetic field, plate tectonic, and many geodynamic and geologic studies. The proposed research will help define the timescale during a period in which it is poorly constrained. The main objective of this overall study is to compile a magnetic anomaly sequence over the Phoenix magnetic lineations in Nauru Basin of the Western Pacific for comparison with similar records previously collected over the Japanese lineations of Pigafetta Basin and the Hawaiian lineations near the Magellan Seamounts. This research cruise will collect Multi-Channel Seismic (MCS) data to define the top of the magnetic source layer within oceanic crust throughout the study area. A subsequent cruise leg will collect multi-scale magnetic data using surface-towed, midwater-towed, and near-seafloor AUV magnetometer deployments. MCS data acquired and processed in advance of the magnetometry cruise will enable informed planning for AUV Sentry dives.