Nature, origin, and petroleum source potential of organic matter at DSDP Leg 56-57 Holes

The samples were canned aboard ship, enabling us to measure also their gas contents. In addition, we analyzed the heavy C15+ hydrocarbons, NSO compounds, and asphaltenes extracted from selected samples.

Our samples form a transect down the trench wall, from Holes 438 and 438A (water depth 1558 m), through Holes 435 and 435A (water depth 3401 m), and 440 (water depth 4507 m), to Holes 434 and 434B (water depth 5986 m). The trench wall is the continental slope of Japan. Its sediments are Cenozoic hemipelagic diatomaceous muds that were deposited where they are found or have slumped from farther up the slope.