Stress in the lithosphere: Inferences from steady state flow of rocks

Mercier, J.; Anderson, Douglas; Carter, Neville L.

doi:10.1007/bf01637104

Cited by 234 publications

(61 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Experimental evidence from metals, ceramics, and silicates (olivine, quartz, pyroxene), shows that during steadystate plastic flow, the grain size produced by dynamic recrystallization decreases as the applied deviatoric stress increases, regardless of the temperature or finite strain (Bird et al, 1969;Twiss, 1977;Mercier et al, 1977). There is no experimental evidence available for plagioclase.…”

Section: Recrystallized Plagioclase Grain-size As a Deviatoric Stressmentioning

confidence: 99%

Normal Ductile Shear Zones at an Oceanic Spreading Ridge: Tectonic Evolution of Site 735 Gabbros (Southwest Indian Ocean)

Cannat¹,

Mével²,

Stakes³

1991

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

We detail the downhole evolution of the ductile deformation in the Site 735 gabbros, using deformed textures as indicators of relative finite-strain intensities, synkinematic metamorphic assemblages as indicators of temperature ranges and of availability of hydrothermal water during deformation, and the size of dynamically recrystallized plagioclase grains as an indicator of relative deviatoric stress intensities. Based on these data, and on the geometry and kinematics of the ductile shear bands throughout the hole, we propose that the ductile deformation recorded at Site 735 resulted from tectonic stretching of the newly accreted gabbroic material at and near the axis of the Southwest Indian Ridge. Apparent changes in the rheological behavior of the gabbros during this extensional ductile deformation suggest a three-step tectonic evolution at progressively lower temperatures and increased availability of hydrothermal water.

show abstract

Section: Recrystallized Plagioclase Grain-size As a Deviatoric Stressmentioning

confidence: 99%

Normal Ductile Shear Zones at an Oceanic Spreading Ridge: Tectonic Evolution of Site 735 Gabbros (Southwest Indian Ocean)

Cannat¹,

Mével²,

Stakes³

1991

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

show abstract

“…The amount of recrystallization ranges from about 10% in the less recrystallized facies to more than 50% in a few samples (Tables 3 and 4). Stress estimates from the neoblast grain size (Mercier et al, 1977;Ross et al, 1980) range from 0.015 to 0.035 GPa in these Porphyroclastic peridotites (Tables 3 and 4).…”

Section: Homogeneous High-temperature Deformationmentioning

confidence: 99%

Deformation History of Peridotites from Mariana Forearc, Conical Seamount, Leg 125

Girardeau¹,

Lagabrielle²

1992

Proceedings of the Ocean Drilling Program

View full text Add to dashboard Cite

Abundant serpentinite seamounts are found along the outer high of the Mariana forearc at the top of the inner slope of the trench. One of them, Conical Seamount, was drilled at Sites 778, 779, and 780 during Leg 125.The rocks recovered at Holes 779A and 780C, respectively, on the flanks and at the summit of the seamount, include moderately serpentinized depleted harzburgites and some dunites. These rocks exhibit evidence of resorption of the orthopyroxene, when present, and the local presence of very calcic-rich diopside in veins oblique to the main high-temperature foliation of the rock.The peridotites, initially well-foliated with locally poikiloblastic textures, show overprints of a two-stage deformation history: (1) a high-temperature (>1000°C), low-stress (0.02 GPa), homogeneous deformation that has led to the present Porphyroclastic textures displayed by the rocks and (2) heterogeneous ductile shearing at a much higher stress (0.05 GPa). This heterogeneous shearing probably describes a single tectonic event because it began at high temperatures, producing dynamic recrystallization of olivine in the shear zone, and ended at low temperatures in the stability field of chlorite and serpentine. In a few samples, olivine shows evidence of quasi-hydrostatic recrystallization at a very high temperature. Here, we propose that this recrystallization was related to fluid/magma percolation, a process that can also account for the resorption of the orthopyroxene and for the late crystallization of diopside veins in the rock.The impregnation by fluid or magma, development of the main high-temperature, low-stress deformation, and subsequent migration recrystallization of olivine probably occurred in a mantle fragment involved in the arc formation. In addition, this mantle has preserved structures that may have formed earlier in the oceanic lithosphere upon which the arc formed.Heterogeneous ductile shear zones in the peridotites may have developed during uplift. The "cold" deformation may have taken place during diapiric rise of hot mantle that underwent subsequent serpentinization or gliding along normal faults associated with the extension of the eastern margin of the forearc.

show abstract

“…Within the past decade there has been considerable interest in the possibility of utilizing dislocation densities, subgrain sizes, and recrystallized grain sizes in rocks as paleopiezometers to infer stress magnitudes (Ball, 1957;Lutton and Sellars, 1969;Twiss, 1977;Mercier et al, 1977;Weathers et al, 1979;. The success of such studies depends in part on one's ability to characterize these deformation microstructures.…”

Section: Introductionmentioning

confidence: 99%