Fluid Exchange between Reacting Bodies of Rock

Abstract

Adjacent units of rock having contrasting chemistries generate fluid reaction products that have different compositions, and which are generated at different stages of pro-grade metamorphism. At constant pressure, a rock that generates a larger volume of fluid than its neighbour will tend to export fluid to its neighbour, particularly if the boundary between the two is not absolutely impermeable. The invasion of one rock by the fluid from another can induce reactions in the invaded rock that produce a new fluid tending to repulse the invader. At different stages, the recipient can become the donor, and vice versa, with the battle lines oscillating until one rock or the other exhausts its buffer capacity.