sentences:  The age of Western Pacific seafloor has been interpreted from seafloor magnetic anomalies correlated to the geomagnetic reversal timescale and confirmed by Ocean Drilling Program scientific drilling.Three major sets of magnetic anomalies have been identified in the area of interest.Each of these lineation sets comprises M-series (mid-Jurassic to mid-Cretaceous) magnetic anomalies that are essentially "growth rings" of the Pacific Plate.