Collaborative Research: Collection of Marine Geophysical Data on Transits of the Nathaniel B. Palmer

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This project will utilize the R/VIB Nathaniel B. Palmer's transit cruises to collect marine geophysical data on targets-of-opportunity in the southern oceans. Because the Palmer generally traverses regions only sparsely surveyed with geophysical instruments, this project represents a cost-effective way to collect important new data. The work's focus is expanding our knowledge of plate motion histories for the Antarctic and surrounding plates. The ultimate goals are improving global plate reconstructions and gaining new insight into general plate kinematics and dynamics and lithospheric rheology. Only slight deviations from the straight routes are required, and we expect to operate on one cruise per year over the three years of the project. The first cruise from New Zealand to Chile will survey a flow line of Pacific-Antarctic plate motion along the Menard fracture zone, which crosses the East Pacific Rise at ~50 S latitude. Swath bathymetry, gravity, magnetics, and a small amount of seismic reflection profiling will be collected to determine the exact trace of the fracture zone and its relationship to the associated gravity anomaly seen in shipboard and satellite radar altimetry data. These observations are critical for precise plate reconstructions, and will provide GPS-navigated locations of a major fracture zone near the northern end of the Pacific-Antarctic boundary. These data will be used in combination with similar data from the Pitman fracture zone at the southwestern end of the plate boundary and magnetic anomalies from previous cruises near the Menard fracture zone to improve high-precision plate reconstructions and evaluate the limits of internal deformation of the Pacific and Antarctic plates. The science plan for cruises in following years will be designed once transit schedules are set. In terms of broader impacts, we plan to teach an on-board marine geophysics class to graduate and undergraduate students on two cruises. The class consists of daily classroom lectures about the instruments and data; several hours per day of watch standing and data processing; and work by each student on an independent research project. We expect to accommodate 15 students per class, including participants from primarily undergraduate institutions with high minority enrollments.