The geophysical data (multibeam bathymetric, 3.5 KHz, magnetic and gravity) will be used to document the character of short wavelength magnetic anomalies within the Cretaceous Quiet Zone (KQZ; 83-120.6 Ma), an approximately 38 million year long interval of constant normal polarity of the geomagnetic field. Since lineated short wavelength magnetic anomalies, attributed to paleointensity fluctuations and short polarity events, have been documented over oceanic crust both older and younger than the KQZ, our expectation is that coherent lineations of geomagnetic origin will also be present in our proposed study area (a region of ultra-fast spreading in the southwestern Pacific). Such coherent features can be used as time markers for tectonic studies within this 38 m.y. interval. If no such correlatable features are found we will have established a major difference between geomagnetic field behavior in the KQZ and at other times. In either case, the character of the non-lineated anomalies together with multibeam bathymetry will provide information on crustal heterogeneity at this ultrafast spreading ridge.

In order to provide the density of magnetic data necessary to distinguish coherent and incoherent magnetic anomaly variations, we propose a 34-day leg to acquire 3 multi-profile swaths of data spanning ~20 m.y. in the KQZ (~110 to 84 Ma). Each profile will consist of a multibeam bathymetry swath, vector and total field gradiometer magnetic data collected by the ship and additional parallel magnetic profiles collected by an unmanned aerial vehicle (UAV). The proposed survey track includes an outbound transit from Wellington, three long profile lines primarily in international waters, and shorter survey lines in the vicinity of the Osbourn Trough.

The goal of the oceanographic and meteorological measurements is to make continuous underway measurements of winds, upper ocean currents (using a hull-mounted acoustic Doppler current profiler), temperature and salinity. These data will be a valuable contribution to ongoing studies of variability in the Southern Ocean. The meteorological data will also be crucial for a portion of the magnetic data acquisition that will utilize unmanned airborne vehicles launched and recovered from the research vessel.