The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Lutz Nasdala - One of the best experts on this subject based on the ideXlab platform.
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Shock-induced formation of kyanite (Al_2SiO_5) from sillimanite within a dense Metamorphic Rock from the Ries crater (Germany)
Contributions to Mineralogy and Petrology, 2004Co-Authors: Volker Stähle, Rainer Altherr, Mario Koch, Lutz NasdalaAbstract:A dense (ρ~3.34 g cm^−3) garnet–sillimanite-rich Metamorphic Rock from the suevite breccia of the Ries impact crater was studied by scanning-electron microscopy and Raman microprobe spectroscopy. In the strongly shocked Rock clast kyanite was formed from sillimanite under momentary high pressures of natural shock waves. Kyanite aggregates were found as thin (~0.3–2.0 μm) seams along grain boundaries between, and fractures within, sillimanite grains. Within these seams kyanite c -axes are oriented perpendicular to original grain boundaries and fractures. In addition, larger (up to 10 μm) isolated kyanite grains were rarely found within host sillimanite. Filamentary kyanite aggregates and isolated crystals typically show shrinkage cracks due to volume decrease (~10%). Locally, broad interstices between sillimanite crystals are filled with aluminosilicate glass containing a high volume fraction of sub-micrometer-sized euhedral crystals. The silica-rich glass suggests incongruent melting of sillimanite at local post-shock temperatures significantly higher than 1,300°C. The edges of adjacent sillimanite grains are thermally and chemically altered. The local generation of temperature spikes is attributed to strong shock wave interactions due to very high shock impedance contrasts.
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shock induced formation of kyanite al2sio5 from sillimanite within a dense Metamorphic Rock from the ries crater germany
Contributions to Mineralogy and Petrology, 2004Co-Authors: Volker Stähle, Rainer Altherr, Mario Koch, Lutz NasdalaAbstract:A dense (ρ~3.34 g cm−3) garnet–sillimanite-rich Metamorphic Rock from the suevite breccia of the Ries impact crater was studied by scanning-electron microscopy and Raman microprobe spectroscopy. In the strongly shocked Rock clast kyanite was formed from sillimanite under momentary high pressures of natural shock waves. Kyanite aggregates were found as thin (~0.3–2.0 μm) seams along grain boundaries between, and fractures within, sillimanite grains. Within these seams kyanite c-axes are oriented perpendicular to original grain boundaries and fractures. In addition, larger (up to 10 μm) isolated kyanite grains were rarely found within host sillimanite. Filamentary kyanite aggregates and isolated crystals typically show shrinkage cracks due to volume decrease (~10%). Locally, broad interstices between sillimanite crystals are filled with aluminosilicate glass containing a high volume fraction of sub-micrometer-sized euhedral crystals. The silica-rich glass suggests incongruent melting of sillimanite at local post-shock temperatures significantly higher than 1,300°C. The edges of adjacent sillimanite grains are thermally and chemically altered. The local generation of temperature spikes is attributed to strong shock wave interactions due to very high shock impedance contrasts.
Manuel Munoz - One of the best experts on this subject based on the ideXlab platform.
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Redox and speciation micromapping using dispersive X‐ray absorption spectroscopy: Application to iron in chlorite mineral of a Metamorphic Rock thin section
Geochemistry Geophysics Geosystems, 2006Co-Authors: Manuel Munoz, Vincent De Andrade, Olivier Vidal, E Lewin, S Pascarelli, Jean SusiniAbstract:[1] The first dispersive μ-XANES mapping is presented here. The experiments have been conducted at the iron K-edge, on the “Dispersive-EXAFS” beamline of the European Synchrotron Radiation Facility (France). The mapping has been performed on a polished thin section of 30 μm of a natural Metamorphic Rock including different types of minerals. Because of the high X-ray absorption due to the thickness of the glass sample holder (∼1 mm), the data have been collected in the fluorescence mode using the so-called “Turbo-XAFS” design. The effective spot size was approximately 10 × 10 microns, and an area 390 × 180 microns in size was mapped. Improvements of the acquisition process allowed collection of each XANES spectrum in 1.5 s and with a step size of 5 microns so that 2808 spectra with full XANES information were collected. Then, automatic procedures for data reduction and mapping reconstruction were developed using Matlab®. The results are maps of iron content, oxidation state, and speciation, with a 5 μm spatial resolution after two-dimensional deconvolution. Subsequent analyses of the reconstructed images provide some quantitative calibrations.
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redox and speciation micromapping using dispersive x ray absorption spectroscopy application to iron in chlorite mineral of a Metamorphic Rock thin section
Geochemistry Geophysics Geosystems, 2006Co-Authors: Manuel Munoz, Vincent De Andrade, Olivier Vidal, E Lewin, S Pascarelli, Jean SusiniAbstract:[1] The first dispersive μ-XANES mapping is presented here. The experiments have been conducted at the iron K-edge, on the “Dispersive-EXAFS” beamline of the European Synchrotron Radiation Facility (France). The mapping has been performed on a polished thin section of 30 μm of a natural Metamorphic Rock including different types of minerals. Because of the high X-ray absorption due to the thickness of the glass sample holder (∼1 mm), the data have been collected in the fluorescence mode using the so-called “Turbo-XAFS” design. The effective spot size was approximately 10 × 10 microns, and an area 390 × 180 microns in size was mapped. Improvements of the acquisition process allowed collection of each XANES spectrum in 1.5 s and with a step size of 5 microns so that 2808 spectra with full XANES information were collected. Then, automatic procedures for data reduction and mapping reconstruction were developed using Matlab®. The results are maps of iron content, oxidation state, and speciation, with a 5 μm spatial resolution after two-dimensional deconvolution. Subsequent analyses of the reconstructed images provide some quantitative calibrations.
Jean Susini - One of the best experts on this subject based on the ideXlab platform.
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Redox and speciation micromapping using dispersive X‐ray absorption spectroscopy: Application to iron in chlorite mineral of a Metamorphic Rock thin section
Geochemistry Geophysics Geosystems, 2006Co-Authors: Manuel Munoz, Vincent De Andrade, Olivier Vidal, E Lewin, S Pascarelli, Jean SusiniAbstract:[1] The first dispersive μ-XANES mapping is presented here. The experiments have been conducted at the iron K-edge, on the “Dispersive-EXAFS” beamline of the European Synchrotron Radiation Facility (France). The mapping has been performed on a polished thin section of 30 μm of a natural Metamorphic Rock including different types of minerals. Because of the high X-ray absorption due to the thickness of the glass sample holder (∼1 mm), the data have been collected in the fluorescence mode using the so-called “Turbo-XAFS” design. The effective spot size was approximately 10 × 10 microns, and an area 390 × 180 microns in size was mapped. Improvements of the acquisition process allowed collection of each XANES spectrum in 1.5 s and with a step size of 5 microns so that 2808 spectra with full XANES information were collected. Then, automatic procedures for data reduction and mapping reconstruction were developed using Matlab®. The results are maps of iron content, oxidation state, and speciation, with a 5 μm spatial resolution after two-dimensional deconvolution. Subsequent analyses of the reconstructed images provide some quantitative calibrations.
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redox and speciation micromapping using dispersive x ray absorption spectroscopy application to iron in chlorite mineral of a Metamorphic Rock thin section
Geochemistry Geophysics Geosystems, 2006Co-Authors: Manuel Munoz, Vincent De Andrade, Olivier Vidal, E Lewin, S Pascarelli, Jean SusiniAbstract:[1] The first dispersive μ-XANES mapping is presented here. The experiments have been conducted at the iron K-edge, on the “Dispersive-EXAFS” beamline of the European Synchrotron Radiation Facility (France). The mapping has been performed on a polished thin section of 30 μm of a natural Metamorphic Rock including different types of minerals. Because of the high X-ray absorption due to the thickness of the glass sample holder (∼1 mm), the data have been collected in the fluorescence mode using the so-called “Turbo-XAFS” design. The effective spot size was approximately 10 × 10 microns, and an area 390 × 180 microns in size was mapped. Improvements of the acquisition process allowed collection of each XANES spectrum in 1.5 s and with a step size of 5 microns so that 2808 spectra with full XANES information were collected. Then, automatic procedures for data reduction and mapping reconstruction were developed using Matlab®. The results are maps of iron content, oxidation state, and speciation, with a 5 μm spatial resolution after two-dimensional deconvolution. Subsequent analyses of the reconstructed images provide some quantitative calibrations.
Mario Koch - One of the best experts on this subject based on the ideXlab platform.
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Shock-induced formation of kyanite (Al_2SiO_5) from sillimanite within a dense Metamorphic Rock from the Ries crater (Germany)
Contributions to Mineralogy and Petrology, 2004Co-Authors: Volker Stähle, Rainer Altherr, Mario Koch, Lutz NasdalaAbstract:A dense (ρ~3.34 g cm^−3) garnet–sillimanite-rich Metamorphic Rock from the suevite breccia of the Ries impact crater was studied by scanning-electron microscopy and Raman microprobe spectroscopy. In the strongly shocked Rock clast kyanite was formed from sillimanite under momentary high pressures of natural shock waves. Kyanite aggregates were found as thin (~0.3–2.0 μm) seams along grain boundaries between, and fractures within, sillimanite grains. Within these seams kyanite c -axes are oriented perpendicular to original grain boundaries and fractures. In addition, larger (up to 10 μm) isolated kyanite grains were rarely found within host sillimanite. Filamentary kyanite aggregates and isolated crystals typically show shrinkage cracks due to volume decrease (~10%). Locally, broad interstices between sillimanite crystals are filled with aluminosilicate glass containing a high volume fraction of sub-micrometer-sized euhedral crystals. The silica-rich glass suggests incongruent melting of sillimanite at local post-shock temperatures significantly higher than 1,300°C. The edges of adjacent sillimanite grains are thermally and chemically altered. The local generation of temperature spikes is attributed to strong shock wave interactions due to very high shock impedance contrasts.
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shock induced formation of kyanite al2sio5 from sillimanite within a dense Metamorphic Rock from the ries crater germany
Contributions to Mineralogy and Petrology, 2004Co-Authors: Volker Stähle, Rainer Altherr, Mario Koch, Lutz NasdalaAbstract:A dense (ρ~3.34 g cm−3) garnet–sillimanite-rich Metamorphic Rock from the suevite breccia of the Ries impact crater was studied by scanning-electron microscopy and Raman microprobe spectroscopy. In the strongly shocked Rock clast kyanite was formed from sillimanite under momentary high pressures of natural shock waves. Kyanite aggregates were found as thin (~0.3–2.0 μm) seams along grain boundaries between, and fractures within, sillimanite grains. Within these seams kyanite c-axes are oriented perpendicular to original grain boundaries and fractures. In addition, larger (up to 10 μm) isolated kyanite grains were rarely found within host sillimanite. Filamentary kyanite aggregates and isolated crystals typically show shrinkage cracks due to volume decrease (~10%). Locally, broad interstices between sillimanite crystals are filled with aluminosilicate glass containing a high volume fraction of sub-micrometer-sized euhedral crystals. The silica-rich glass suggests incongruent melting of sillimanite at local post-shock temperatures significantly higher than 1,300°C. The edges of adjacent sillimanite grains are thermally and chemically altered. The local generation of temperature spikes is attributed to strong shock wave interactions due to very high shock impedance contrasts.
Volker Stähle - One of the best experts on this subject based on the ideXlab platform.
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Shock-induced formation of kyanite (Al_2SiO_5) from sillimanite within a dense Metamorphic Rock from the Ries crater (Germany)
Contributions to Mineralogy and Petrology, 2004Co-Authors: Volker Stähle, Rainer Altherr, Mario Koch, Lutz NasdalaAbstract:A dense (ρ~3.34 g cm^−3) garnet–sillimanite-rich Metamorphic Rock from the suevite breccia of the Ries impact crater was studied by scanning-electron microscopy and Raman microprobe spectroscopy. In the strongly shocked Rock clast kyanite was formed from sillimanite under momentary high pressures of natural shock waves. Kyanite aggregates were found as thin (~0.3–2.0 μm) seams along grain boundaries between, and fractures within, sillimanite grains. Within these seams kyanite c -axes are oriented perpendicular to original grain boundaries and fractures. In addition, larger (up to 10 μm) isolated kyanite grains were rarely found within host sillimanite. Filamentary kyanite aggregates and isolated crystals typically show shrinkage cracks due to volume decrease (~10%). Locally, broad interstices between sillimanite crystals are filled with aluminosilicate glass containing a high volume fraction of sub-micrometer-sized euhedral crystals. The silica-rich glass suggests incongruent melting of sillimanite at local post-shock temperatures significantly higher than 1,300°C. The edges of adjacent sillimanite grains are thermally and chemically altered. The local generation of temperature spikes is attributed to strong shock wave interactions due to very high shock impedance contrasts.
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shock induced formation of kyanite al2sio5 from sillimanite within a dense Metamorphic Rock from the ries crater germany
Contributions to Mineralogy and Petrology, 2004Co-Authors: Volker Stähle, Rainer Altherr, Mario Koch, Lutz NasdalaAbstract:A dense (ρ~3.34 g cm−3) garnet–sillimanite-rich Metamorphic Rock from the suevite breccia of the Ries impact crater was studied by scanning-electron microscopy and Raman microprobe spectroscopy. In the strongly shocked Rock clast kyanite was formed from sillimanite under momentary high pressures of natural shock waves. Kyanite aggregates were found as thin (~0.3–2.0 μm) seams along grain boundaries between, and fractures within, sillimanite grains. Within these seams kyanite c-axes are oriented perpendicular to original grain boundaries and fractures. In addition, larger (up to 10 μm) isolated kyanite grains were rarely found within host sillimanite. Filamentary kyanite aggregates and isolated crystals typically show shrinkage cracks due to volume decrease (~10%). Locally, broad interstices between sillimanite crystals are filled with aluminosilicate glass containing a high volume fraction of sub-micrometer-sized euhedral crystals. The silica-rich glass suggests incongruent melting of sillimanite at local post-shock temperatures significantly higher than 1,300°C. The edges of adjacent sillimanite grains are thermally and chemically altered. The local generation of temperature spikes is attributed to strong shock wave interactions due to very high shock impedance contrasts.