The role of serpentinization in exhumation of high- to ultra-high-pressure metamorphic rocks

Analysis of physical processes involved in serpentinization show that it can lead to a significant reduction in density, huge volume increase and generate giant pressure within serpentinizing rocks. Combined together, these factors make the serpentinization process a very important one for the start and support of exhumation of high- and ultra-high-pressure rocks. Serpentinization can generate a significant buoyancy force, as well as forces capable of horizontal displacing of an exhuming block. Exhumation of high-grade rocks to the surface requires the presence of an external force, and it cannot be accomplished by buoyancy alone. te relationships between exhumation and serpentinization, serpentinized peridotites and HP–LT/UHP–LT rocks, and co-existence of eclogites and blueschists with thrusts and nappes containing peridotites, serpentinites, or ophiolites point to the significant role of serpentinization in exhumation. Formal analysis of the viscous properties of the lithosphere illustrates that exhumation within the continental crust is extremely slow, that its velocity increases with an increase of slab size, and that the velocity value during the subduction process should be greater than during exhumation. ted by serpentinization process, pressure can play an important role in both forcing an exhuming block up and/or detaching the upper part of the subducting slab from its bottom part. An absence of serpentinites of the Archean age proves that serpentinization cannot play a significant role in exhumation of high-grade rocks in the Archean.