Analysis of crystallographic preferred orientations of experimentally deformed Black Hills Quartzite
The crystallographic preferred orientations (textures) of three samples of Black Hills Quartzite (BHQ) deformed experimentally in the dislocation creep regimes 1, 2 and 3 (according to Hirth and Tullis, 1992) have been analyzed using electron backscatter diffraction (EBSD). All samples were defo...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2017-10-01
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| Series: | Solid Earth |
| Online Access: | https://www.solid-earth.net/8/1095/2017/se-8-1095-2017.pdf |
| _version_ | 1828411510265741312 |
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| author | R. Kilian R. Heilbronner |
| author_facet | R. Kilian R. Heilbronner |
| author_sort | R. Kilian |
| collection | DOAJ |
| description | The crystallographic preferred orientations (textures) of three samples of
Black Hills Quartzite (BHQ) deformed experimentally in the dislocation creep
regimes 1, 2 and 3 (according to Hirth and Tullis, 1992) have been analyzed
using
electron backscatter diffraction (EBSD). All samples were deformed to relatively high strain at temperatures of
850 to 915 °C and are almost completely
dynamically recrystallized. A texture transition from peripheral [<i>c</i>] axes
in regime 1 to a central [<i>c</i>] maximum in regime 3 is observed. Separate pole
figures are calculated for different grain sizes, aspect ratios and long-axis
trends of grains, and high and low levels of intragranular deformation
intensity as measured by the mean grain kernel average misorientation (gKAM).
Misorientation relations are analyzed for grains of different texture
components (named Y, B, R and <i>σ</i> grains, with reference to previously
published <q>prism</q>, <q>basal</q>, <q>rhomb</q> and <q><i>σ</i><sub>1</sub></q> grains). Results
show that regimes 1 and 3 correspond to clear end-member textures, with regime
2 being transitional. Texture strength and the development of a central
[<i>c</i>]-axis maximum from a girdle distribution depend on deformation
intensity at the grain scale and on the contribution of dislocation creep,
which increases towards regime 3. Adding to this calculations of resolved
shear stresses and misorientation analysis, it becomes clear that the
peripheral [<i>c</i>]-axis maximum in regime 1 is not due to deformation by basal
〈<i>a</i>〉 slip. Instead, we interpret the texture transition as a
result of different texture forming processes, one being more efficient at
high stresses (nucleation or growth of grains with peripheral [<i>c</i>] axes),
the other depending on strain (dislocation glide involving prism and rhomb
〈<i>a</i>〉 slip systems), and not as a result of temperature-dependent activity of different slip systems. |
| first_indexed | 2024-12-10T12:31:19Z |
| format | Article |
| id | doaj.art-ae4af278eb544824b118ddbda9c16c8f |
| institution | Directory Open Access Journal |
| issn | 1869-9510 1869-9529 |
| language | English |
| last_indexed | 2024-12-10T12:31:19Z |
| publishDate | 2017-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Solid Earth |
| spelling | doaj.art-ae4af278eb544824b118ddbda9c16c8f2022-12-22T01:48:48ZengCopernicus PublicationsSolid Earth1869-95101869-95292017-10-0181095111710.5194/se-8-1095-2017Analysis of crystallographic preferred orientations of experimentally deformed Black Hills QuartziteR. Kilian0R. Heilbronner1Department of Environmental Sciences, Geological Institute, Bernoullistrasse 32, 4056 Basel, SwitzerlandDepartment of Environmental Sciences, Geological Institute, Bernoullistrasse 32, 4056 Basel, SwitzerlandThe crystallographic preferred orientations (textures) of three samples of Black Hills Quartzite (BHQ) deformed experimentally in the dislocation creep regimes 1, 2 and 3 (according to Hirth and Tullis, 1992) have been analyzed using electron backscatter diffraction (EBSD). All samples were deformed to relatively high strain at temperatures of 850 to 915 °C and are almost completely dynamically recrystallized. A texture transition from peripheral [<i>c</i>] axes in regime 1 to a central [<i>c</i>] maximum in regime 3 is observed. Separate pole figures are calculated for different grain sizes, aspect ratios and long-axis trends of grains, and high and low levels of intragranular deformation intensity as measured by the mean grain kernel average misorientation (gKAM). Misorientation relations are analyzed for grains of different texture components (named Y, B, R and <i>σ</i> grains, with reference to previously published <q>prism</q>, <q>basal</q>, <q>rhomb</q> and <q><i>σ</i><sub>1</sub></q> grains). Results show that regimes 1 and 3 correspond to clear end-member textures, with regime 2 being transitional. Texture strength and the development of a central [<i>c</i>]-axis maximum from a girdle distribution depend on deformation intensity at the grain scale and on the contribution of dislocation creep, which increases towards regime 3. Adding to this calculations of resolved shear stresses and misorientation analysis, it becomes clear that the peripheral [<i>c</i>]-axis maximum in regime 1 is not due to deformation by basal 〈<i>a</i>〉 slip. Instead, we interpret the texture transition as a result of different texture forming processes, one being more efficient at high stresses (nucleation or growth of grains with peripheral [<i>c</i>] axes), the other depending on strain (dislocation glide involving prism and rhomb 〈<i>a</i>〉 slip systems), and not as a result of temperature-dependent activity of different slip systems.https://www.solid-earth.net/8/1095/2017/se-8-1095-2017.pdf |
| spellingShingle | R. Kilian R. Heilbronner Analysis of crystallographic preferred orientations of experimentally deformed Black Hills Quartzite Solid Earth |
| title | Analysis of crystallographic preferred orientations of experimentally deformed Black Hills Quartzite |
| title_full | Analysis of crystallographic preferred orientations of experimentally deformed Black Hills Quartzite |
| title_fullStr | Analysis of crystallographic preferred orientations of experimentally deformed Black Hills Quartzite |
| title_full_unstemmed | Analysis of crystallographic preferred orientations of experimentally deformed Black Hills Quartzite |
| title_short | Analysis of crystallographic preferred orientations of experimentally deformed Black Hills Quartzite |
| title_sort | analysis of crystallographic preferred orientations of experimentally deformed black hills quartzite |
| url | https://www.solid-earth.net/8/1095/2017/se-8-1095-2017.pdf |
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