Paleomagnetic properties of igneous rocks from several DSDP and ODP sites, western Pacific

Oceanic basalts and other related igneous rocks are considered excellent recorders of the Earth's paleomagnetic field. Consequently, basalt core paleomagnetic data are valuable for the constraints they provide on plate tectonic motions, especially for oceanic plates such as the Pacific. Unfortunately, few Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) boreholes have been cored very deeply into the ocean crust. The result is that there are only a few sites at which a large enough number of basalt flows have been cored to properly average secular variation (e.g., Kono, 1980, doi:10.2973/dsdp.proc.55.135.1980; Cox and Gordon, 1984, doi:10.1029/RG022i001p00047). Furthermore, there are a number of sites where basaltic core samples were retrieved but the cores were not measured. Often this occurs because leg scientists had more important sections to work on, or the section was ignored because it was too short to record enough time to average secular variation and obtain a reliable paleolatitude. Even though it may not be possible to determine a precise paleolatitude from such short sections, measurements from a small number of flows are important because they can be combined with other coeval paleomagnetic data from the same plate to calculate a paleomagnetic pole (Gordon and Cox, 1980, doi:10.1111/j.1365-246X.1980.tb02642.x; Cox and Gordon, 1984, doi:10.1029/RG022i001p00047). For this reason, I obtained samples for paleomagnetic measurements from eight Pacific sites (169, 170, 171, 581, 597, 800, 803, and 865), most of which have not been previously measured for paleomagnetism.