Data report: temporal variation in natural remanent magnetization observed for Pacific plate basement rocks: compilation from legacy data and new paleomagnetism and rock magnetism data from seafloor basalts cored during Expedition 320/321

Abstract

Previous rock magnetism data compilations from oceanic basement rocks show that intensity of natural remanent magnetization (NRM) decays with age from 0 to 30 Ma and then increases prior to 40 Ma. This temporal trend in NRM is regarded as tentative. One of the problems seems to be that these compilations were made from NRM data without regard to the oceanic plates where the samples were collected. As a case study, we have compiled basement rock NRM data from Deep Sea Drilling Project and Ocean Drilling Program sites on the Pacific plate only. The present compilation results in 103 NRM data points for the 0–50 and 110–170 Ma intervals. We also conducted rock magnetism and paleomagnetism studies on basement rocks recovered from five sites drilled during Integrated Ocean Drilling Program Expedition 320/321 in order to provide new data. These samples yield 13 new NRM data points for the 24–50 Ma interval.