The Blake Ridge, offshore South Carolina, was drilled at three sites, Sites 994, 995, and 997, during Ocean Drilling Program Leg 164. During the cruise, shipboard paleomagnetic measurements were performed to establish a magnetostratigraphy to refine age dates of the sediments. Shipboard measurements yielded a preliminary reversal stratigraphy (Shipboard Scientific Party, 1996, doi:10.2973/odp.proc.ir.164.1996). The routine paleomagnetic measurements of continuous core sections with the pass-through cryogenic magnetometer after alternating field (AF) demagnetization at 20 mT showed downhole inclination profiles with negative and positive intervals in the sections recovered with the advanced hydraulic piston corer (APC). The cryogenic results agreed with the results from analysis of discrete samples. The reversal stratigraphy was constructed based on the cryogenic and discrete sample results.Although the primary reversal stratigraphy was constructed for each site during the cruise, the boundaries of magnetic polarity zones were poorly constrained because there were insufficient polarity measurements obtained from the discrete sample analysis (Only one or two samples per core were made in the intervals recovered with the APC; fewer were made in the intervals cored with the extended core barrel [XCB]. Each core is 9.5 m). Therefore, I conducted shore-based paleomagnetic analyses to determine more precise locations of the magnetic polarity zones and reversals for the APC-cored intervals at Sites 994, 995, and 997.In this report, I describe progressive AF demagnetization behavior of the samples and present paleomagnetic declination, inclination, and intensity data before and after AF demagnetization. Magnetic polarity zones are defined for the APC-cored intervals of Sites 994, 995, and 997, and these are presented with nannofossil data and interpreted nannofossil zonations (Okada, 2000, doi:10.2973/odp.proc.sr.164.232.2000).

Sediment depth is given in mbsf. Declination (core) = declination referred to arbitrary core coordinates, (relative to the x-axis direction defined by the double-line fiducial mark in the center of the core liner on the working half of the cores), declination (oriented) = declination oriented to geographic coordinates (relative to geographic north) with the Tensor tool.

Supplement to: Hiroki, Yoshihisa (2000): Data Report: Magnetostratigraphy of the Pleistocene-late Pliocene sediments of ODP Sites 994, 995, and 997, Blake Ridge. In: Paull, CK; Matsumoto, R; Wallace, PJ; Dillon, WP (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 164, 1-8