has a water depth of approximately 2,650 fathoms. The slopes of the 

 basin are furrowed with submarine canyons, which at one time channelled 

 deposits to the deep-sea floor (Fairbridge, 1966; Standard, 1961). The 

 present rate of accumulation from terrestrial sources is low; consequently, 

 pelagic material overlies the turbidite deposits. 



Sediment Identification . The gravity corer obtained 225 centimeters 

 of material. The top 100 centimeters consisted of homogeneous deep-sea 

 red clay, while the remaining portion of the core was composed of a 

 gray-green silty clay. A visual examination of the core found no other 

 distinctive layering. The red clay and gray-green silty clay were 

 classified as inorganic silts of high compressibility (MH) (Unified 

 Classification System) and silty clays (Trilinear System). The red clay 

 and silty clay had median diameters of approximately 0.0015 and 0.0025 

 millimeter, respectively. The percentages of sand, silt, and clay size 

 particles for the red clay sample were 3, 28, and 69, respectively. The 

 gray-green clay was composed of 37. sand size particles, 367« silt size, 

 and 617o clay size. Although the carbonate carbon and organic carbon 

 compound contents of both samples were low (for example 1.07, and 3.07 o ), 

 the gray-green silty clay did have the higher value of the two determin- 

 ations . 



Vane Shear Strength and Index Properties . The shear strength and 

 index properties are plotted in Figure 7. No unusual trends occur. 

 The length-to-diameter ratio of the core exceeds 35 for the lower incre- 

 ment, therefore, a high undisturbed in-situ strength might be expected. 



Station F 



Geologic Considerations . Station F is located on the western side 

 of the New Hebrides Basin, one of three major basins in the Coral Sea. 

 Pelagic red clays and globigerina oozes dominate surface materials of 

 the basin (Fairbridge, 1966). Fine-grained silt-clays (including volcanic 

 ash), deposited by once-active turbidity currents, lie beneath the 

 surface sediments (Hamilton, 1970). Water depth at the site is approx- 

 imately 2,400 fathoms. 



Sediment Identification . The gravity corer obtained 220 centimeters 

 of red clay and globigerina ooze. The sediment profile was composed of 

 50 centimeters of red clay above 80 centimeters of mottled red clay 

 and globigerina ooze. The final 90 centimeters of sediment were globig- 

 erina ooze. The 60-centimeter trip corer verified the results from the 

 gravity corer. The Unified Classification System defined the red clay 

 as a clay of high plasticity (CH) and the globigerina ooze as an inorganic 

 silt of high compressibility (MH) . The Trilinear System designates the 

 two samples as a silty clay and a sand-silt-clay, respectively. The red 

 clay had a median diameter equal to 0.0019 millimeter, while the diameter 

 for the ooze was 0.006 millimeter. The percentages of sand, silt, and 



25 



