The rheological study of Mariana serpentine muds will place strong constraints on the mechanics that generate and emplace the serpentine muds, maintain the conduits, and construct the seamounts. These muds are thus orders of magnitude weaker than salt and are, in fact, comparable in strength to common deep-sea pelagic clays. The rate at which the muds rise relative to the fluids will likely influence the water-rock reactions and the character of the slab signal in fluids from these mud volcanoes. Although total fluid budgets are difficult to ascertain in any convergent margin, we suggest that they are more readily determined at nonaccretionary active margins because the hydrologic flow systems operate on longer time scales than do those at accretionary margins. Attempts to determine the total fluid budgets at accretionary active margins have been hindered by the presence of lateral heterogeneity and transient flow processes.
Lateral heterogeneity results in different flow rates and compositions along strike of the margin.
Transient flow apparently results largely from the valve-like influence of the accretionary complexes themselves. Sediment properties vary with fluid pressure, and fluid pressure varies as a function of fluid production rate and transient hydrologic properties. Thus, the accretionary system acts as both a seal and a relief valve on the fluid flow system. The absence of such a short time scale, fluid pressure, and formation properties modulator at nonaccretionary systems should allow fluids to escape more steadily. To test this hypothesis, the physical nature of fluid flow at nonaccretionary settings must be determined.