Paleomagnetic of Cretaceous basalts from ODP Hole 129-802A

Cretaceous basalts have been recovered at several Ocean Drilling Program and Deep Sea Drilling Project sites where basement of Jurassic age was predicted. Sites 800 and 802, Leg 129, both fall in this category. We have examined the paleomagnetic properties of 25 basalt samples from Site 802 in order to establish a paleolatitude for the site at the time of basalt emplacement and to compare the results to those from Deep Sea Drilling Project Site 462. Mean natural remanent magnetization intensity for the Site 802 basalts was found to be approximately 12 A/m consistent with typical oceanic basalts. Mean stable inclination is -34.7° ± 2.2 which implies a paleolatitude of approximately 19.4°S. This is very similar to the paleolatitudes calculated for Site 462 basalts and suggests - along with similarities in geochemistry, magnetic properties, and projected age of Site 802 basalt emplacement - both contemporaneity of and a possible source link between the two sites.

(Table 1) Radiolarians of ODP Hole 129-801B

Middle Jurassic radiolarians have been recovered from the western Pacific for the first time. The oldest faunas are assigned to the middle and upper Tricolocapsa conexa Zone, indicating a Bathonian/Callovian age. The faunas contain more than 30 species and are characterized by an abundance of small nassellarians with a constricted distal end. The faunas compare well with Tethyan faunas, and are especially similar to Japanese faunas.