Figure 8. Simulated chlorinity (A) and ³⁷Cl profiles (B) for Site 997 generated by the hydrochemical model of Egeberg and Dickens (1999) without the advection term. The different curves are for time spans 1, 5, 10 and 20 Ma, respectively, during which diffusion has been active. The model runs reach steady state after about 20 Ma. In this model, hydrate dissociation at the base of the hydrate zone (at 452 mbsf) is the only source of fresh water at depth in the subsurface. For details see text.