Annotated record of the detailed examination of Mn deposits from DSDP Leg 91 (Holes 595, 595A, 596, 596A)

Sites 595 and 596 of DSDP Leg 91 are located in one of the most poorly studied tracts of seafloor in the world at the time of the survey. During a preparation survey done by the R/V Melville a particular question of geologic regional significance was the lithologic nature of the "reverberant layer" detected in the Southwest Pacific Basin, especially to the north of the site. The drilling also beared on two important aspects of the oceanic crustal composition: the chemistry and petrology of the lavas erupted at rapidly spreading ridges, and the nature and degree of alteration experienced by those lavas over the 100+ m.y. of their posteruptive history.