An Aeromagnetic Survey of the Chile Ridge

The Chile Ridge is a major branch of the global ridge system. The magnetic lineations formed by seafloor spreading on the Chile Ridge have recorded the relative motion of the Antarctic and Nazca plates since the breakup of the Farallon plate around 25 million years ago. These magnetic lineations contain adetailed record of the tectonic history of this region during the Neogene. However, the spreading history of the Chile Ridge cannot be accurately resolved with the current set of magnetic data collected by ships. An aeromagnetic survey of the Chile Ridge would enable the PIs to map the magnetic anomaly pattern on the Chile Ridge in considerable detail. Funds are provided to support the participation of Lamont scientists in both the acquisition and interpretation phases of the survey to be run by Naval Research Lab (NRL). The aeromagnetics data, along with existing shipboard marine geophysical data and GEOSAT/SEASAT geoid altimetry data, will be used to reconstruct a detailed tectonic history of the Chile Ridge during the Neogene. This detailed tectonic history will provide the basis for studying the effect on the Chile Ridge and Nazca plate of a series of Neogene ridge-trench collisions.