Submarine Canyons 



49 



cently discovered deep-sea channels extend- 

 ing from the canyons would require almost 

 complete loss of the ocean if they too were 

 formed by subaerial processes. In an at- 

 tempt to circumvent these difficulties, sug- 

 gestions for removal of water have been 

 based on continental flexure (Bourcart, 

 1938), sudden change of rate of earth rota- 

 tion (Hess and MacClintock, 1936), and 

 sudden changes in position of the axis of 



earth rotation (Ma, 1952). Each of these 

 proposals has its own set of difficulties plus 

 the common ones of wide distribution and 

 great depth of the canyons. 



Forming the second series of hypotheses 

 are those based on processes that can oper- 

 ate below sea level. Perhaps the first one 

 advocated was that of fault valleys (Lawson, 

 1893a; de Andrade, 1937). Although many 

 submarine canyons (La Jolla, and possibly 



STATUTE 



MILES 



FAN OF SANTA CLARA RIVER 



Figure 48. Profiles of submarine canyons of southern California compared with stratigraphy where known. Compiled 

 from many sources. Symbols are as follows: arrow, shoreline; K, Cretaceous; E, Eocene; M, Miocene; P, Pliocene; 

 Q, Quaternary; R, postglacial (on sea floor letters show sites of dateable rock samples). 



