New Phoenix Magnetic Anomaly Data Confirms Global Nature of Jurassic Quiet Zone and Provides Insight Into Early Pacific Spreading

Abstract We demonstrate the presence of the oldest identifiable marine magnetic anomalies in the Phoenix lineations of the western Pacific based on careful assessment of new data. Recently acquired sea surface magnetic anomalies and multichannel seismic profiles confirm magnetic signals recorded within the Middle‐Jurassic to Early Cretaceous basement. Our data definitively show coherent marine magnetic anomalies from M29 to M42 and possibly older. This closes the triangle of three mid‐ocean ridge systems into a region of the western Pacific with a center around (16°N,159°E) where spreading flow lines merge. Our compilation of three complete lineation sets from the Japanese, Hawaiian, and now Phoenix lineations to M42 provides a new bound for the Jurassic Quiet Zone and models of geomagnetic field history and global tectonics.