(Table 1) Magnetic viscosity coefficient, VRM and NRM of DSDP Hole 6-57

THE magnetic properties of the basalts which form layer 2 of the oceanic lithosphere are important because of their relevance to the hypothesis (Vine and Matthews, 1963, doi:10.1038/199947a0) of seafloor spreading. Most studies of these magnetic properties have been carried out on basalts obtained from dredge hauls taken predominantly from ocean ridge systems and fracture zones. These constitute special areas of the oceanic crust where the sediment cover is negligible. It is of interest to compare the magnetic properties of the dredged basalts with samples recovered from holes drilled through the overlying sediments into the basaltic layer at places distant from ridge axes. Samples obtained from the abandoned Mohole project and, more recently, from the Deep Sea Drilling Project (DSDP) possessed magnetic properties similar to those of dredged basalts (Cox and Doell, 1962, doi:10.1029/JZ067i010p03997; Lowrie et al., 1973, doi:10.1016/0012-821X(73)90198-2). Here I describe highly unstable magnetic characteristics found in basalts from DSDP hole 57.

(Table 1) Concentrations and isotopic ratios of sulfur and carbon in acid conglomerates from DSDP Hole 57-439

The sulfur content of one rhyolite and four dacite conglomerates was found to be low - from 9 to 97 ppm - similar to that of Quaternary andesites and basalts of the Japanese Islands. However, the d34S values of these samples are unexpectedly high - +23 to +35 per mill - relative to troilite from the Canon Diablo meteorite. The sulfide/sulfate ratios vary among the five samples from 0 to 13. No significant isotope fractionation seems to exist between sulfate and sulfide sulfurs. Carbon in these samples is predominantly in the form of carbonate (and probably CO2). It ranges in concentration from 128 to 721 ppm and in d13C from -2.5 to -20.7 per mill relative to PDB.