Annotated record of the detailed examination of Mn deposits from DSDP Leg 60 (Holes 452, 452A, 453, 454, 454A, 456, 456A, 458, 459B, 460, 460A, 461, 461A)

Two consecutive drilling legs (Legs 59 and 60) were assigned to drill an east-west transect of sites along latitude 18°N, from the Mariana Basin of the Pacific Ocean to the oldest inactive island arcs and back-arc spreading basins of the Philippine Sea. The western (older, inactive) half of this transect (Philippine Sea, Palau-Kyushu Ridge, Parece Vela Basin, and the West Mariana Ridge-Sites 447-451) was drilled during Leg 59. The objective of Leg 60 was to sample the tectonically active eastern portion of the transect in a closely spaced series of holes across the presently opening back-arc basin (Mariana Trough, Site Survey Target SP-4: Sites 453-456), the Mariana arc itself (Site Survey Target SP-3b: Site 457), the Mariana fore-arc region (Site Survey Target SP-3, Sites 458 and 459), and deep within the Mariana Trench (Site Survey Target SP-2: Sites 460 and 461). In addition, one site (Site Survey Target SP-1: Site 452) was drilled on the Pacific plate seaward of the trench to obtain a reference section of sediments and oceanic crust being delivered to the trench.