During Leg 65, four sites were drilled near the mouth of the Gulf of California where high sedimentation rates made it possible to sample young oceanic crust near the ridge crest. The oldest sediments cored were upper Pliocene siltstones (Site 483); the samples at the other sites (482, 484, and 485) were all Quaternary in age. A series of 80 sediment samples, most of them hemipelagic clays, were examined by semiquantitative X-ray diffraction and Carbonate Bomb techniques to determine their mineralogy and carbonate contents. The results of this study may be used to determine their provenance and diagenesis.

Sediment depth is given in mbsf. <1 = minor, ?0 = questionable presence.

Supplement to: Schumann, Dieter (1983): X-ray mineralogy of sediments recovered during DSDP Leg 65. In: Lewis, BTR; Robinson, P; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 65, 391-397