Citation

Crowell JC. J. Geol. 1952; 60(1): 58-83.

Copyright

(Copyright © 1952, University of Chicago Press)

DOI

10.2307/30057012

PMID

unavailable

Abstract

The characteristics of California submarine canyons between Monterey and San Diego differ from land canyons, suggesting that their origin is not subaerial: longitudinal profiles are steeper than those of most land canyons; profiles are more irregular; canyons head near or at sea-level but extend to different depths, some greater than 10,000 feet; etc. Geologic data show that the heads of Redondo, Hueneme, Mugu, and Newport canyons cut Upper Pleistocene and Recent sediments and that no land stream has issued into the Redondo Canyon head during the late Pleistocene and Recent. These arguments, with others, suggest that California submarine canyons were cut by submarine processes which are still operating today in some canyons. Wave-approach and refraction studies along the California coast, with observations, show that considerable sediment brought to the sea by land rivers is moved along the coast by longshore processes. California submarine canyons occur where (1) a supply of sediment is brought to canyon heads by these shore processes, (2) a relatively steep offshore slope heads close to shore, and (3) the transporting power of the longshore current slackens, usually because of coastal configuration. The canyons are probably eroded by the seaward movement downslope under gravity of sediment by some kind of sediment flow, turbidity, density, or 'suspension current.