Simulating coseismic deformation of quartz in the middle crust and fabric evolution during postseismic stress relaxation — An experimental study

Trepmann, Claudia A.; Stöckhert, Bernhard; Dorner, Dorothée; Moghadam, Rasoul Hamidzadeh; Küster, Martina; Röller, K.

doi:10.1016/j.tecto.2007.05.005

Cited by 89 publications

(117 citation statements)

References 55 publications

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“…For this stage of rapid loading, strain rate and stresses attained come close to those expected for natural deformation (Trepmann et al 2007;Druiventak et al, 2012). Consequently, microfabrics developed in these experiments are expected to correspond to those formed in nature.…”

Section: Introductionsupporting

confidence: 64%

“…Starting material is pure natural vein quartz (CR1; > 99.9 % quartz) with grain size of ∼ 1 mm and average dislocation density on the order of 10 12 m −2 , as described by Trepmann et al (2007). Cylindrical samples with a length of ∼ 7 mm and a diameter of ∼ 3. of 0.1 mm to prevent reaction between specimen and the surrounding pressure transmitting medium, which is a mixture of 65.5 mole % CsCl and 34.5 mole % NaCl.…”

Section: Methodsmentioning

confidence: 99%

“…In these cases, resulting characteristic microstructures are not destroyed by subsequent creep. For quartz the situation is more complicated, as microstructures created during quasi-instantaneous loading at temperatures above about 300 • C are modified or entirely obliterated in the course of subsequent creep during stress relaxation (Trepmann and Stöckhert, 2003). Laboratory experiments designed to explore the effects of such overprint require high temperatures, in order to speed up processes and to keep stresses at a level expected for nature.…”

Section: Introductionmentioning

confidence: 99%

“…We follow the original concept of "kick and cook" experiments, designed to simulate coseismic loading and postseismic relaxation in the uppermost plastosphere (Trepmann et al, 2007;Druiventak et al, 2011Druiventak et al, , 2012. In this study, we replace the "cook" procedure, which denotes a stage of high temperature and nominally zero differential stress, by a more realistic "creep" stage at high temperature and moderate residual stress, during which microstructures created in the initial stage of high-stress deformation ("kick") become modified during further deformation.…”

Section: Introductionmentioning

confidence: 99%

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Short-wavelength undulatory extinction in quartz recording coseismic deformation in the middle crust – an experimental study

Trepmann

Stöckhert

2013

Solid Earth

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Abstract. Deformation experiments are carried out on natural vein quartz in a modified Griggs-type solid medium apparatus to explore the preservation potential of microfabrics created by crystal-plastic deformation at high stress, overprinted during subsequent creep at lower stress. A corresponding stress history is expected for the upper plastosphere, where fault slip during an earthquake causes quasiinstantaneous loading to high stress, followed by stress relaxation. The question is whether evidence of crystal-plastic deformation at high stress, hence an indicator of past seismic activity, can still be identified in the microstructure after overprint by creep at lower stresses. First, quartz samples are deformed at a temperature of 400 • C and constant strain rate of 10 −4 s −1 ("kick"), and then held at 900 to 1000 • C at residual stress ("creep"). In quartz exclusively subject to high-stress deformation, lamellar domains of slightly differing crystallographic orientation (misorientation angle < 2 • ) and a few tens of micrometres wide occur. In the transmission electron microscope (TEM), these areas show a high density of tangled dislocations and cellular structures. After "kick and creep" experiments, pronounced short-wavelength undulatory extinction (SWUE) is observed in the polarization microscope. The wavelength of SWUE is up to 10 µm, with oscillatory misorientation of up to a few degrees. TEM inspection reveals domains with high density of dislocations and differing diffraction contrast bound by poorly ordered dislocation walls. Only zones with exceptional damage generated during high-stress deformation are replaced by small new grains with a diameter of about 10 to 20 µm, forming strings of recrystallized grains. For large original grains showing SWUE, the Schmid factor for basal a glide is found to be high. SWUE is taken to reflect high-stress crystal-plastic deformation, the modified microstructure being sufficiently stable to be recognized after subsequent creep as an indicator of past seismic activity.

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Section: Introductionsupporting

confidence: 64%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Short-wavelength undulatory extinction in quartz recording coseismic deformation in the middle crust – an experimental study

Trepmann

Stöckhert

2013

Solid Earth

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“…The localization of recrystallization along twins might also concur in developing the large misorientation typically observed at the boundary of many recrystallized shear bands in quartz (e.g. Vernooij et al 2006b;Trepmann et al 2007), as the accumulated lattice distortion modified the previous twin boundary to a general high-angle boundary.…”

Section: Mechanism Of Dynamic Recrystallizationmentioning

confidence: 84%

The effect of Dauphiné twinning on plastic strain in quartz

Menegon

Piazolo

Pennacchioni

2010

Contrib Mineral Petrol

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We present an electron backscatter diffraction analysis of five quartz porphyroclasts in a greenschist facies (T = 300-400°C) granitoid protomylonite from the Arolla unit of the NW Alps. Mechanical Dauphiné twinning developed pervasively during the incipient stage of deformation within two porphyroclasts oriented with a negative rhomb plane {z} almost orthogonal to the compression direction (z-twin orientation). Twinning was driven by the anisotropy in the elastic compliance of quartz and resulted in the alignment of the poles of the planes of the more compliant positive rhomb {r} nearly parallel to the compression direction (r-twin orientation). In contrast, we report the lack of twinning in two porphyroclasts already oriented with one of the {r} planes orthogonal to the compression direction. One twinned porphyroclast has been investigated with more detail. It shows the localization of much of the plastic strain into discrete r-twins as a consequence of the higher amount of elastic strain energy stored by r-twins in comparison to z-twins. The presence of Dauphiné twins induced a switch in the dominant active slip systems during plastic deformation, from basal \a[ (regions without twinning) to {p} and {p 0 } \a[(pervasively twinned regions). Dynamic recrystallization is localized along an r-twin and occurred dominantly by progressive subgrain rotation, with a local component of bulging recrystallization. Part of the recrystallized grains underwent rigid-body rotation, approximately about the bulk vorticity axis, which accounts for the development of large misorientation angles. The recrystallized grain size piezometer for quartz yields differential stress of 100 MPa. The comparison of this palaeostress estimate with literature data suggests that mechanical Dauphiné twinning could have a potential use as palaeopiezometer in quartz-bearing rocks.

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High‐temperature fracturing and subsequent grain‐size‐sensitive creep in lower crustal gabbros: Evidence for coseismic loading followed by creep during decaying stress in the lower crust?

et al. 2015

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The mechanism of shear zone formation in lower crustal, relatively "dry" rocks is still poorly understood. We have studied the high-temperature deformation of the Hasvik gabbro (northern Norway) which commences by fracturing. The 10-20 μm wide fractures show little displacement. The fine-grained plagioclase and orthopyroxene in the fractures lack a crystallographic preferred orientation (CPO) or a systematic crystallographic orientation with respect to the host grains. Fractures grade into narrow shear zones, which are composed of fine (10-20 μm), equant grains of recrystallized plagioclase, amphibole, and pyroxene. Recrystallized plagioclase and pyroxene have compositions different from the magmatic grains, suggesting that they have formed by nucleation and growth. Based on conventional plagioclase-amphibole thermobarometry, the shear zones have formed at temperatures and pressures of 700-750°C and 0.5-0.6 GPa. The observed primary minerals cut by fractures suggest high-temperature fracturing in the absence of high pore pressures, which implies a high strength of the lower crustal gabbros and high stresses at fracturing. The shear zones are characterized by the lack of CPO and a small grain size, suggesting that the mechanism of deformation of the fine-grained plagioclase and orthopyroxene has been grain boundary sliding accommodated by diffusive mass transfer. The amphibole grains have strong CPOs, which most likely result from oriented growth and/or rigid body rotations during deformation. The process that initiated the fracturing and subsequent viscous creep in the Hasvik gabbro may have resulted from a process of coseismic loading followed by creep during decaying stress in the lower crust.

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Simulating coseismic deformation of quartz in the middle crust and fabric evolution during postseismic stress relaxation — An experimental study

Cited by 89 publications

References 55 publications

Short-wavelength undulatory extinction in quartz recording coseismic deformation in the middle crust – an experimental study

Short-wavelength undulatory extinction in quartz recording coseismic deformation in the middle crust – an experimental study

The effect of Dauphiné twinning on plastic strain in quartz

High‐temperature fracturing and subsequent grain‐size‐sensitive creep in lower crustal gabbros: Evidence for coseismic loading followed by creep during decaying stress in the lower crust?

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