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ABSTRACT

The northeast corner of the Pacific Ocean is a region of turbidity-current activity. Cores from this area are dominated by very fine-grained sand and medium-grained silt that grade upward to clay. The results presented in this article are based on 217 textural analyses of turbidite layers comprising 30 piston cores.

It is possible to distinguish proximal and distal facies of turbidites using characteristics of layering, grading and texture. Features of the proximal facies include wide range of layer thickness, maximum layer thickness, non-grading, truncation of grading, textural reversals, and sand at the base of graded layers. Areas beyond main routes of submarine flows are sites of episodic addition of silt-through clay-sized sediment. The proportion, thickness, and mean grain size of the silt decreases with increasing distance from the main avenues of flow.