Petrography and chemical composition of the lava flows at DSDP Leg 55 Holes

Of the five lava flows recovered at Hole 430A, the upper four flows are typical hawaiites and the lowest flow is tholeiite. Three lava flows of alkalic basalts recovered at Hole 432A on Nintoku Seamount are petrographically and chemically similar to the analogous rocks from the Hawaiian Islands.

Ninety-six cooling units, from 163 to 550 meters sub-bottom, were sampled at the re-entry Hole 433C. Most of them are lava flows and others are secondary thin flows or flow lobes from fissures of basic flows. The three uppermost flows are alkalic basalts.