They are divided into four lithologic units. Interbedding occurs on a scale of 20-80 cm. The tagged basement consists of basalt. Core-core correlation between the 5 holes successfully established a continuous composite record down to 110 mbsf. More detailed work is in progress for cores below this depth.
Velocities increase slowly downhole with very slight variation.
High velocities correspond to low porosity values. These diatom oozes contain assemblages of diatoms, radiolarians, and planktonic foraminifers indicative of extensive upwelling of cool waters associated with the California Current. The radiolarian assemblages are the best-preserved Miocene examples from an intense upwelling province, and include numerous new species never observed before. Likewise, the planktonic foraminifer assemblages provide a rare insight into the characteristics of faunas associated with intense Miocene upwelling. The sequence of changes in planktonic foraminifers suggests the need to establish a new zonation for the southern California Current system.