TwinCalc: A multitool for calcite twinning based stress analysis

Rez, Jiří

doi:10.1016/j.acags.2020.100020

Cited by 4 publications

(12 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Later, others [3,9,66,[91][92][93] emphasized the respective limitations of previous methods. It is only recently that a real effort has been dedicated to proposing new methods/inversion schemes to go beyond older methods [58,60,66,67]. To the best of the authors' knowledge, however, the technique by [66] has to date been applied neither to experimentally or naturally deformed samples nor in extensive regional studies.…”

Section: Brief Review Of Recent Methods and Improvements Of Calcite T...mentioning

confidence: 99%

“…In some instances, measurements can be assisted by a software that significantly speeds up the measurements and makes them more accurate. The software calculates the orientation of the C-axis from the orientations of the optically visible crystallographic planes (twin or cleavage planes) using the angular relationships between the C-axis and the crystallographic planes in the crystal [57,58]. While bringing true progress in data collection, the software [57] does not allow one to collect data from a crystal having only one visible plane (twin or cleavage).…”

Section: Universal Stagementioning

confidence: 99%

“…Among the available techniques that analyse calcite twins in term of stress, some are designed to determine paleostress orientations only [54,77,86], paleostress magnitudes only [26,87] or both [58,60,[65][66][67]88,89]. In this section, we consider only the techniques using calcite twins to determine principal stress orientations (and stress ratios).…”

Section: Use Of Calcite Twins As Markers Of Stress Regime: Inversion ...mentioning

confidence: 99%

“…While acknowledging that CSIT generally provides stress determinations consistent with fault and fracture analysis [8,52,80,82,[94][95][96][97][98][99][100][101][102][103][104][105], Yamaji [66] states that the CSIT solutions appear to be unstable, mainly due to the selection method (i.e., the penalization function) of the solution tensors, which is only dependent on the last twinned plane taken into account in each solution tensor tested. A more detailed theoretical criticism of the earlier methods [88,89] and CSIT [65] can be found in [58,66].…”

Section: Etchecopar Technique: Csitmentioning

confidence: 99%

“…TwinCalc [58] is a freeware application for stress analysis based on calcite twinning. On the one hand, TwinCalc provides a number of tools for (1) twin data acquisition using an optical microscope equipped with a U-stage; (2) statistical analysis and plotting of twin data; and (3) stress analysis of twin data using most of the classical methods ( [54,108] for stress orientations and [26,87] for differential stress).…”

Section: Rez Technique: Twincalcmentioning

confidence: 99%

See 4 more Smart Citations

Calcite Twin Formation, Measurement and Use as Stress–Strain Indicators: A Review of Progress over the Last Decade

et al. 2021

View full text Add to dashboard Cite

Mechanical twins are common microstructures in deformed calcite. Calcite twins have been used for a long time as indicators of stress/strain orientations and magnitudes. Developments during the last decade point toward significant improvements of existing techniques as well as new applications of calcite twin analysis in tectonic studies. This review summarises the recent progress in the understanding of twin formation, including nucleation and growth of twins, and discusses the concept of CRSS and its dependence on several factors such as strain, temperature and grain size. Classical and recent calcite twin measurement techniques are also presented and their pros and cons are discussed. The newly proposed inversion techniques allowing for the use of calcite twins as indicators of orientations and/or magnitudes of stress and strain are summarized. Benefits for tectonic studies are illustrated through the presentation of several applications, from the scale of the individual tectonic structure to the continental scale. The classical use of calcite twin morphology (e.g., thickness) as a straightforward geothermometer is critically discussed in the light of recent observations that thick twins do not always reflect deformation temperature above 170–200 °C. This review also presents how the age of twinning events in natural rocks can be constrained while individual twins cannot be dated yet. Finally, the review addresses the recent technical and conceptual progress in calcite twinning paleopiezometry, together with the promising combination of this paleopiezometer with mechanical analysis of fractures or stylolite roughness.

show abstract

Section: Brief Review Of Recent Methods and Improvements Of Calcite T...mentioning

confidence: 99%

Section: Universal Stagementioning

confidence: 99%

Section: Use Of Calcite Twins As Markers Of Stress Regime: Inversion ...mentioning

confidence: 99%

Section: Etchecopar Technique: Csitmentioning

confidence: 99%

Section: Rez Technique: Twincalcmentioning

confidence: 99%

See 3 more Smart Citations

Calcite Twin Formation, Measurement and Use as Stress–Strain Indicators: A Review of Progress over the Last Decade

et al. 2021

View full text Add to dashboard Cite

show abstract

3D active fault kinematic behaviour reveals rapidly alternating near-surface stress states in the Eastern Alps

Baroň,

Melichar,

Sokol

et al. 2024

View full text Add to dashboard Cite

Stress variations in the Earth's crust need to be understood in both the spatial and temporal domains to address a number of pressing societal issues. In this paper, precise three dimensional records of fault kinematic behaviour obtained by mechanical extensometers are used to investigate changes in stress states along major faults in the Eastern Alps. The monitored faults are fractures with evident Upper Quaternary displacement and are directly attributed to their master tectonic structures. The results demonstrate that activity at the submillimetric scale is highly episodic; periods of repose are punctuated by conspicuous reactivation events affecting one or more of the displacement components. An original approach named the SMB2018 method is used to define the stress state associated with each fault reactivation event. The outputs evidence significant short term changes in the local stress regime. The directions of the principal normal stresses calculated from these reactivation events present generally similar patterns for both compressional and extensional stress states. Consequently, submillimetric fault activity cannot be controlled by a rotating stress field; such shifts can only be caused by a change in the magnitude of the individual principal normal stresses so that the maximum compression changes to the minimum and vice versa.

show abstract

Application of Electron Backscatter Diffraction to Calcite-Twinning Paleopiezometry

2022

View full text Add to dashboard Cite

Electron backscatter diffraction (EBSD) was used to determine the orientation of mechanically twinned grains in Carrara marble experimentally deformed to a small strain (≤4%) at room temperature and at a moderate confining pressure (225 MPa). The thicknesses of deformation twins were mostly too small to permit determination of their orientation by EBSD but it proved possible to measure their orientations by calculating possible twin orientations from host grain orientation, then comparing calculated traces to the observed twin traces. The validity of the Turner & Weiss method for principal stress orientations was confirmed, particularly when based on calculation of resolved shear stress. Methods of paleopiezometry based on twinned volume fraction were rejected but a practical approach is explored based on twin density. However, although twin density correlates positively with resolved shear stress, there is intrinsic variability due to unconstrained variables such as non-uniform availability of twin nucleation sites around grain boundaries that imposes a limit on the achievable accuracy of this approach.

show abstract

TwinCalc: A multitool for calcite twinning based stress analysis

Cited by 4 publications

References 18 publications

Calcite Twin Formation, Measurement and Use as Stress–Strain Indicators: A Review of Progress over the Last Decade

Calcite Twin Formation, Measurement and Use as Stress–Strain Indicators: A Review of Progress over the Last Decade

3D active fault kinematic behaviour reveals rapidly alternating near-surface stress states in the Eastern Alps

Application of Electron Backscatter Diffraction to Calcite-Twinning Paleopiezometry

Contact Info

Product

Resources

About