18 +


 -20 -+ Barbados
 Costa Rica
 x Nankai
 -22 A Peru


 -24 1
 0 02 04 06 08 1
 Porositl

Figure 2-5. Plot of laboratory derived permeability measurements from Barbados, Costa
 Rica, Nankai, and Peru subduction zones superimposed on outline of Neuzil's
 (1994) plot for argillaceous sediments. As compared to Neuzil's (1994) paper,
 the axes have been transposed.

Effects of Depositional Environment

 According to Boggs (2001) there is little agreement regarding the classification of

deep-sea sediments and thus, suggested classifications range from those that are largely

genetic to those that are largely descriptive. Unfortunately there is no single

classification that take into account both genesis and descriptive properties of all kinds of

deep-sea sediments (Boggs, 2001). Thus, here I used generalized descriptions used by

Boggs (2001) to categorize hemipelagic and pelagic sediments. Hemipelagic muds are

defined as mixtures of fine-grained terrigenous mud with biogenic remains that are

deposited under very low current velocities. According to Stow and Piper (1984),

hemipelagic muds contain more than 5% biogenic remains and a terrigenous component

of more than 40%. The terrigenous component of the hemipelagic muds are commonly

composed of fine terrigenous quartz, feldspar, micas, and clay minerals while biogenic