Organic carbon, age, lithology, and CPI-alkenes at DSDP Sites 57-440 and 56-436

"Bound" and "free" solvent-extractable lipids have been examined from Sections 440A-7-6, 440B-3-5, 440B-8-4, 440B-68-2, and 436-11-4. The compound classes studied include aliphatic and aromatic hydrocarbons, ketones, alcohols, and carboxylic acids. Carotenoids and humic acids have also been examined. The quantitative results are considered in terms of input indicators, diagenesis parameters, and structural classes. A difference in input is deduced across the Japan Trench, with a higher proportion of autochthonous components on the western inner trench slope compared with the more easterly, outer trench, wall and greater input in the early Pleistocene than in the Miocene. A variety of diagenetic transformations is observed at Site 440 as sample depth increases. Results are compared with those of samples from Atlantic Cretaceous sediments and from the Walvis Bay high productivity area.

(Table 1) Typical trace-fossil occurrences in DSDP Holes 56-436 and 56-435A

Trace fossils are in places abundant in cores from DSDP Leg 56 sites. They are particularly rich in the pelagic-clay sequence at Site 436. Some significant trace fossils, including Zoophycos, Teichichnus, Chondrites, rind and solid burrows, and pellet-armored rods, are described. The ichnofauna, except for pellet-armored rods in diatomaceous mudstone of the landward trench slope, is characterized by cosmopolitan bathyal to abyssal forms.