Frictional properties of olivine at high temperature with applications to the strength and dynamics of the oceanic lithosphere

Abstract

[1] Faulting and brittle deformation of mantle rocks occurs in many tectonic settings such as oceanic transform faults, oceanic detachment faults, subduction zones, and continental rifts. However, few data exist that directly explore the frictional properties of peridotite rocks. Improved constraints on the brittle deformation of peridotite is important for a more complete understanding of the rheological properties of the lithosphere. Furthermore, our comparatively detailed understanding of plastic deformation in olivine allows us to explore the possible role of thermally activated intracrystalline deformation mechanisms in macroscopically brittle processes. It has been hypothesized, and some experimental data indicate, that plastic yielding by dislocation glide (low temperature plasticity) determines the direct effect in the rate and state frictional constitutive formulation. Plastic flow may also have important implications for the blunting or necking at asperity contacts that influences the time and/or displacement dependent friction evolution effect and frictional healing. We present results from saw cut experiments on fine grained synthetic olivine fault gouge conducted in a gas-medium deformation apparatus in the temperature range of 400-1000 C with 100 MPa confining pressure. We conducted velocity stepping tests to explore the rate and temperature dependence of sliding stability. We also conducted slide-hold-slide experiments to investigate the time and temperature dependence of fault zone restrengthening (frictional healing). The mechanical data and microstructural observations allow us to explore the role of thermally activated processes in frictional sliding. The data indicate systematic temperature dependenceof rate and state variables that can be attributed to plastic yielding at grain to grain contacts. We explore the implications of such temperature dependent behavior for controlling the base of the seismogenic zone in the oceanic lithosphere, and we seek insight into possible mechanistic models for the interactions between fracture and flow that could lead to improved constraints on the strength of the lithosphere.Citation: King, D. S. H., and C. Marone (2012), Frictional properties of olivine at high temperature with applications to the strength and dynamics of the oceanic lithosphere,

The Mechanics of Frictional Healing and Slip Instability During the Seismic Cycle

“…This form has the advantage of explicitly accounting for the effect of strain rate localization (see Rathbun and Marone, 2010;Sleep et al, 2000). To model strain rate localization and to illuminate the relationship between the RSF laws and other rheologies, eqn [8] can be rewritten as a flow law (King and Marone, 2012;Rice et al, 2001) To model strain rate localization and to illuminate the relationship between the RSF laws and other rheologies, eqn [8] can be rewritten as a flow law (King and Marone, 2012;Rice et al, 2001)…”

“…This formulation makes a clear connection between the RSF laws, thermally activated creep processes, strain localization, and strain delocalization during healing (e.g., Beeler, 2007;Berthoud et al, 1999;Heslot et al, 1994;King and Marone, 2012;Rice et al, 2001;Ruina, 1980;Sleep et al, 2000). For example, if m is understood as a creep stress s, then eqn [10] is readily rearranged as a logarithmic flow law s % S ln _ e=_ e o ð Þ, where S % a is a constant equal to kT/s c O (kT is energy in temperature units, s c is contact indentation strength, and O is activation volume for the thermally activated process), or a power-law creep relation s % A_ e n , if the exponent n is small, where A is a constant.…”

Micromechanisms of creep in clay‐rich gouge from the Central Deforming Zone of the San Andreas Fault

“…In fault rocks composed of phyllosilicates or olivine, the parameter a is consistent with the rate dependence for dislocation glide, A glide [ Beeler et al , ; Boettcher et al , ; King and Marone , ]. To evaluate the importance of glide in the CDZ gouge, we compare the normalized rate dependence, a / μ 0 , with the normalized rate dependence for dislocation glide in single crystals of muscovite [ Mares and Kronenberg , ] and biotite [ Kronenberg et al , ].…”

Rate‐and‐state friction properties of the Longitudinal Valley Fault from kinematic and dynamic modeling of seismic and aseismic slip

“…The dependence of quasi‐static (slow‐rate) friction properties on bulk temperature has been well established [ He et al , ; Blanpied et al , , ; King and Marone , ; den Hartog et al , ; Niemeijer and Collettini , ; Verberne et al , ]. Typically, at high enough temperatures, the rate‐and‐state properties transition from VW to VS, the feature often encapsulated in the depth dependence of friction properties as also done in our dynamic models.…”