62 



HISTORY OF THE OCEANS 



Fig. 4. Porosity vs. depth below the sea floor for red cla>- and Glohigerina ooze 

 with hydrostatic uplift. A curve is shown for Skeels' shale (1950) assuming 300 m 

 of unlithified clay overburden and hydrostatic uplift of solids; actual field condi- 

 tions are shown for the Tertiary of the Gulf Coast (Dickinson, 1953). 



but that generalizations were possible for the argillaceous sedi- 

 ments. 



During the mechanical rearrangement stage (90% to 75% 

 porosity), under gravitational pressure, free water in pore spaces 

 is squeezed out together with some adsorbed water. During the 

 dewatering stage (75% to 35% porosity) the expulsion of free 



