Coring in two adjacent holes at DSDP Site 585 (13.5°N, 156.8°E) recovered lower Tertiary through Aptian sedimentary rocks. The paleolatitudes of each hole from the late Aptian through Paleocene were derived from an extensive set of paleomagnetic minicores. Each sample underwent progressive thermal demagnetization, and the characteristic direction of magnetization was derived from the region of stable directions. True mean inclinations were computed for each lithologic unit and for each stage or pair of stages, using the method of Kono (1980b). The results yield average paleolatitudes of 1°S for the Paleocene-Maestrichtian, 7°S for the Santonian-Turonian, and 15°S for the Albian-late Aptian. The Aptian-Albian paleolatitudes agree with paleomagnetic results from DSDP Sites 462 and 289 in the western central Pacific. The average rate of northward drift by the site was about 30 km/m.y. through the Late Cretaceous and earliest Tertiary. The Maestrichtian paleolatitude agrees with a Pacific paleomagnetic pole computed by Gordon (1982) from North Pacific data, but the site is about 12° farther north than predicted by Campanian and Cenomanian North Pacific poles (Gordon, 1983; Gordon and Cox, 1980). Recovery of the latest Cretaceous-early Tertiary sediments was inadequate to allow unique determination of the magnetostratigraphy. No reversed interval could be identified within the late Aptian or early Albian.

Supplement to: Ogg, James G (1986): Paleolatitudes and magnetostratigraphy of Cretaceous and lower Tertiary sedimentary rocks, Deep Sea Drilling Project Site 585, East Mariana Basin, Western Central Pacific. In: Moberly, R; Schlanger, SO; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 89, 629-645