Control of fluids on deformation of rocks Academic Article uri icon

abstract

  • Fluids of many compositions, concentrations and pressures, are ubiquitous throughout the continental lithosphere, exerting strong control on the deformation properties and processes of rocks both by mechanical means and by complex chemical rock-fluid interactions. Fluids of meteoric and juvenile origin, released by compaction, dehydration reactions, melting, and degassing, commonly during large-scale tectonic events, flow by means of thermal convection, advection (infiltration), and surface and intracrystalline diffusion. These fluids transport mass for distances ranging from the grain scale to hundreds of kilometres; fracture zones provide favourable conduits for flow. Abnormal pore pressures, recorded at all metamorphic grades, develop intermittently during syntectonic deformation, enhancing fluid infiltration by promoting increased porosity and permeability, hydraulic fracturing and severe grain size reductions. The infiltrating fluids enhance hydrolytic weakening, several grain boundary mechanisms, and reaction kinetics in a feedback manner so that strain is commonly localized into semibrittle and ductile shear zones. Large-scale detachments may take place along these shear zones at virtually any depth below the uppermost few kilometres, which, when combined with softening resulting from depth-dependent petrological and geochemical segregations, form a rheological stratigraphy. The rheology of the lithosphere through time has been governed by a combination of bulk rock flow and localized deformation is shear zones, both of which have been aided or controlled by pervasive dynamic rock-fluid interactions. 1990 The Geological Society.

published proceedings

  • Geological Society London Special Publications

author list (cited authors)

  • Carter, N. L., Kronenberg, A. K., Ross, J. V., & Wiltschko, D. V.

citation count

  • 67

complete list of authors

  • Carter, NL||Kronenberg, AK||Ross, JV||Wiltschko, DV

publication date

  • January 1990