A STUDY OF LOCAL VARIABILITY IN MARINE SEDIMENTS * 



By Richard G. Bader 



Department of Oceanography, University of Washington 

 Seattle 5, Washington, U.S.A. 



Introduction 



The sampling problem involved in obtaining any natural sample is 

 often exceedingly complex and has received much consideration in the 

 literature. In the process of obtaining any one sediment sample by 

 means of a coring tube or other sampling device, only an exceedingly 

 minute portion of the sea bottom is sampled. In a strict sense any single 

 sample is merely representative of the exact spot sampled. Unless the 

 process of sampling continues systematically in this and adjacent areas, 

 radial extrapolation from the sample is subject to great error, with any 

 single sample being representative of only itself. The introduction of 

 this limitation on problems of sedimentation or sedimentary environ- 

 mental studies, whether they be physical, chemical, or biological, pre- 

 sents a serious handicap. In order to proceed with any sedimentai-y 

 research it is necessary to know the limitations of the samples obtained 

 and to understand, at least to some degree, the existing local variations 

 and the probabilities for such variations. 



The purpose of this paper is to briefly present some of the initial 

 results concerning a problem of sampling marine sediments in the region 

 of Puget Sound, in the State of Washington. The information to date 

 consists of the data from a particle size analysis of the bottom sediments 

 obtained along an east-west traverse of Puget Sound, about 12 miles 

 north of the city of Seattle. 



Regional Description 

 Puget Sound is a pre-existent valley system which has been partially 

 drowned by the sea. It is one of the deepest salt water basins in the 

 United States. The mid-channel bottom area exceeds 900 feet in depth 

 in some localities. Depths of 600 or more feet below sea level are usually 

 encountered in the channel portions of the Sound. Except for local 

 areas, the shore slopes and underwater slopes are steep; inclines of 25 

 degrees are common. 



♦ This work was supported by the Office of Naval Research under Contract No. N8onr- 

 620/III, Project NR 083-012, with the Department of Oceanography, University of Washington, 

 Seattle 5, Washington. 



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