STRATIGRAPHY OF THE DEEP-SEA FLOOR 61 



"Assumptions: A progressive porosity decrease under pressure with no lithification 

 which is probably a rare situation. Properties: density of solids, 2.69 gr/cc; water density 

 1.05 gr/cc; initial porosity, 66%. 



'' Laughton ran the test on a Globigerina ooze with 54% CaCOs. 



Lithification of Clay and Calcareous Oozes 

 Clay 



The process by which a silt or clay is consolidated and lithified 

 to form a shale was studied by a number of persons in the decade 

 1925 to 1935. In his classic study Hedberg (1936) used a combina- 

 tion of soil mechanics knowledge and a field study of undistorted 

 shales in Venezuela to in\'estigate the relationship of pressure, 

 depth, porosity, density, and lithification. Hedberg mentioned at 

 the start of his study that there could never be an exact quantita- 

 tive solution to the relations between pressure, volume, and lithifi- 

 cation in clays and shales because there were too many variables, 



