Initial Reports of the Deep Sea Drilling Project, 34

We have made paleomagnetic measurements and investigated the magnetic mineralogy of 24 samples of basalt and diabase from Sites 319, 320, and 321 on the Nazca plate. Sample distributions, locations, and ages of overlying sediments are as follows: Site 319, Hole 319, lat 13°01.04'S, long 101°31.46'W, 2 samples, early Miocene (N8); Site 319, Hole 319A, (same coordinates and age), 12 samples. Site 320, Hole 320B, lat 9°00.40'S, long 83°31.8O'W, 2 samples, late Oligocene (N2); Site 321, lat 12°01.29'S, long 81°54.24'W, 8 samples, late Eocene (P16). The objectives were (1) to investigate the stability of the natural remanent magnetization (NRM), (2) to evaluate an improved method of alternating-field (AF) demagnetization, (3) to determine the directions of the magnetically stable components of NRM and the approximate in-situ intensities of NRM, (4) to identify the ferrimagnetic minerals and determine their degree of oxidation, and (5) to relate this oxidation to the magnetic characteristics of the minerals.