Constituents : All material greater than 250 microns in diameter was separated 

 from each subsample used for size analysis and examined under a binocular microscope. 

 This procedure was followed to determine the nature and the source of the sedimentary 

 material and to estimate grossly the abundance of various components present. 



Near-flank sand-sized particles are composed predominantly of skeletal and non- 

 skeletal calcium carbonate. The skeletal debris is represented by the tests of plank- 

 tonic and benthonic foraminifera, pteropods, ostracods, calcareous algae, molluscs, 

 coral debris, alcynarian spicules, and echnoid spines and plates. Nonskeletal parti- 

 cles are oolites, casts of foraminifera, and oolitn-like particles described by llling 

 (1954) as grains of aragonite matrix. In addition to the calcareous material, small 

 amounts of siliceous sponge spicules were encountered. 



In the majority of the near-flank cores fibrous plant-like material is present and 

 serves to aggregate numerous fine particles which ordinarily would fall into a smaller 

 particle-size category. 



No visual or mineralogical examination of the material comprising the silt and 

 lutlte fraction was made; however. X-ray analysis by Rusnak and Nesteroff (1962) 

 revealed that the finer fraction becomes more calcific with decreasing grain size, 

 and the less than 2 micron fraction contains about equal amounts of calcite and 

 aragonite. 



Placement of this sediment into one of the existing deep-sea sediment classifica- 

 tions after Revel le (1944) or Olausson (1961) is unwarrented as these categorizing 

 schemes were originated for the constituents normally found in deep-sea areas away 

 from rich sources of shallow-water material. Likewise, classification of the sediment 

 under one of the many schemes for shallow-water sediments is not feasible due to the 

 large quantity of deep-sea components. Consequently, the bottom material from the 

 near-flank area will be referred to as calcareous ooze, and no generic implications 

 ore attached . 



Organic Carbon : Organic carbon content of the top centimeter of the near-flank 

 sediments is high relative to samples from the central area of the TOTO. The lowest 

 value of organic carbon content from near-flank samples was 0.21 percent, the highest 

 2.48 percent, and the average 1 .22 percent. These values are lower than those ob- 

 tained on the shallow banks surrounding the channels where values range from 3 to 6 

 percent organic content (Trask, 1955) but are higher than the average deep-sea sedi- 

 ments which contain 0.3 to 1 .5 percent total organic matter (Schott, in Trask, 1955). 



A strong odor of HoS was noticeable from all the near-flank cores. Over half of 

 the cores from this group were measured for hydrogen Ion concentration (pH) at the top 

 and bottom immediately after being brought aboard ship^ and in all instances the pH 

 was between 6.0 and 7.2. In contrast, cores from the central or axial area show litho- 

 logic features Indicative of oxidizing rather than reducing conditions. 



Mass Physical Properties : Measurements of sediment density, water content, void 

 ratio, and porosity were made, and the results are presented In Table II. In some 

 instances, cores suitable for particle size analysis were not considered suitable for mass 



21 



