156 



coast o The sediments in these regions are affected by cvirrents 

 and waves at the present time, and as a consequence reflect 

 present environmental conditions. 



Most of the shelf sediments are well-sorted, Moderately- 

 and poorly=-sorted sediments on the basin slope and on the 

 shelf occur in areas where relic sediments are found, and/or 

 where authigenic minerals and large accumulations of shell 

 fragments form part of the deposit. 



There is a tendency for the shelf sediments to show better 

 sorting near the edge of the shelf, perhaps as a result of 

 stronger currents or turbulence which tend to produce better 

 sorting in the sediments. 



With the exclusion of the area where the head of Redondo 

 Canyon comes close to shore, the sediment pattern is essentially 

 the same from shore to an offshore distance of four miles. 

 This pattern consists of an offshore gradation from sand to 

 sandy silt. The areas where relic sand is still exposed are 

 probably areas where sediment by^passing takes place. Also, 

 the shelf sediments are probably reworked occasionally and the 

 finer fragments are removed during intermittent erosion and 

 deposition. 



At the head of Santa Monica Canyon, and inshore from the 

 central shelf projection 4 to 6 miles from shore, there are 

 sediments which are generally coarser than those nearer the 

 coast. The existence of relic sediments near the surface 

 indicates that sedimentation must be slow at present. This 

 may be due to either a smaller supply on this section of the 

 shelf, or to greater turbulence which prevents permanent 



