increment of red clay occurred at the top of both cores. The sediment 

 log below that depth included approximately 10 centimeters of tan clay 

 above a gray clay. The material was classified by the Unified Classi- 

 fication System as an inorganic silt of high compressibility (MH) . The 

 Trilinear System defined the material as a silty clay. The material 

 had a median diameter equal to 0.001 millimeter. The percentages of 

 sand, silt, and clay size particles were 5, 19, and 76. Carbonate car- 

 bon and organic carbon accounted for approximately 1.57o of the material. 



Vane Shear Strength and Index Properties . The vane strength and 

 index properties are plotted in Figure 23. The strength profiles 

 increase drastically in the first 25 centimeters. Since a discontinuity 

 of similar magnitude did not occur in the index properties, some unusual 

 soil characteristic seems to exist at this level. Soil disturbance would 

 not normally increase the strength of a cohesive material, particularly 

 to the magnitude recorded. If the measurements are neglected, the 

 strength profile (with the trip core data) behaves as might be expected. 

 The increment in question may derive its strength from cementation; 

 however, the carbonate carbon and organic carbon content determinations 

 are low. 



Station R 



Geologic Considerations . Station R is located in the northern 

 portion of the Malacca Straits. Depth at the site is 50 fathoms. Bottom 

 conditions at. the site are closely related to strong currents, debouching 

 rivers, climatic variations, and the proximity of bordering land masses 

 (Keller and Richards, 1967). Sediments consist of muddy sands and minor 

 amounts of calcium carbonate (shells and foraminiferal tests). Kaolinite 

 constitutes the dominant clay minerals; lesser amounts of illite and 

 montmorillonite are also found. Much of the area was, at one time, above 

 sea level (Fairbridge, 1966). 



Sediment Identification . Four gravity cores were obtained from 

 Station R. The general core log revealed a fine gray shelly sand (0 to 

 16 centimeters) and a stiff gray clay (75 to 120 centimeters). The 

 percentages of sand, silt, and clay size particles for the three samples 

 are listed in Table 5. The median diameters and carbon contents of the 

 samples are also included. 





Table 5 



Properties at Station R 







Particle Size (%) 







Soil Type 





Median Diameter 

 (mm) 



Carbonate Carbon 

 Organic Carbon (7o) 



Sand 



Silt 



Clay 













Compound 



Shelly Sand 



84 



5 



11 



0.2 



6.0 



Sand 



83 



5 



12 



0.17 



5.0 



Clay 



24 



24 



52 



0.004 



3.0 



34 



