Annotated record of the detailed examination of Mn deposits from DSDP Site 34, Leg 5 (Core 5-34-17)

Site 34 had been located by the JOIDES Pacific Advisory Panel to be over a negative magnetic anomaly (31 million years B.P.) immediately to the east of Anomaly 10 (Site 33). The primary objective was to obtain samples of basement and basal sediment to provide comparison between adjacent positive and negative magnetic anomalies. A second objective was to obtain samples which would permit an analysis of the variability in sediment over relatively short distances (about 10 miles). Although basement had not been reached at Site 33 because of the unexpected chert, the use of a massive diamond bit at Site 34 permitted coring through the chert to basement at 383 meters below the sea floor. Even though the near basement sections of the paired sites (33 and 34) could not be compared, comparison would be possible above the chert layer.