Ca-rich majorite derived from high-temperature melt and thermally stressed hornblende in shock veins of crustal rocks from the Ries impact crater (Germany)

Stähle, Volker; Altherr, Rainer; Nasdala, Lutz; Ludwig, Thomas

doi:10.1007/s00410-010-0531-1

Cited by 27 publications

(34 citation statements)

References 60 publications

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“…Notably, this same spatial association is well documented from meteorites and terrestrial impact structures, where high‐pressure minerals such as ringwoodite, tuite, tissintite, stishovite, lingunite, and majorite are found almost exclusively within or in the environs of shock melt (e.g., Langenhorst and Poirier ; Xie and Sharp ; Fritz and Greshake ; Biren and Spray ; Stähle et al. ; Walton ; Walton et al. ).…”

Section: Discussionsupporting

confidence: 56%

“…; Stähle et al. ). The composition of garnets formed from biotite at the SRIS was constrained using EMP wavelength‐dispersive spectrometry (WDS), TEM EDX, and synchrotron XRD‐based structure analysis techniques.…”

Section: Discussionmentioning

confidence: 98%

“…Shock veins have been documented from a handful of impact structures, including Manicouagan (Canada; Biren and Spray ), Ries (Germany; Stähle et al. ), Steen River (Canada; Walton et al. ), and Vredefort (South Africa; e.g., Martini ).…”

Section: Discussionmentioning

confidence: 99%

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Investigating the response of biotite to impact metamorphism: Examples from the Steen River impact structure, Canada

Walton

Sharp

et al. 2017

Meteorit & Planetary Scien

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Abstract-Impact metamorphic effects from quartz and feldspar and to a lesser extent olivine and pyroxene have been studied in detail. Comparatively, studies documenting shock effects in other minerals, such as double chain inosilicates, phyllosilicates, carbonates, and sulfates, are lacking. In this study, we investigate impact metamorphism recorded in crystalline basement rocks from the Steen River impact structure (SRIS), a 25 km diameter complex crater in NW Alberta, Canada. An array of advanced analytical techniques was used to characterize the breakdown of biotite in two distinct settings: along the margins of localized regions of shock melting and within granitic target rocks entrained as clasts in a breccia. In response to elevated temperature gradients along shock vein margins, biotite transformed at high pressure to an almandine-Ca/Fe majorite-rich garnet with a density of 4.2 g cm À3 . The shock-produced garnets are poikilitic, with oxide and silicate glass inclusions. Areas interstitial to garnets are vesiculated, in support of models for the formation of shock veins via oscillatory slip, with deformation continuing during pressure release. Biotite within granitic clasts entrained within the hot breccia matrix thermally decomposed at ambient pressure to produce a fine-grained mineral assemblage of orthopyroxene + sanidine + titanomagnetite. These minerals are aligned to the (001) cleavage plane of the original crystal. In this and previous work, the transformation of an inosilicate (pargasite) and a phyllosilicate (biotite) to form garnet, an easily identifiable, robust mineral, has been documented. We contend that in deeply eroded astroblemes, high-pressure minerals that form within or in the environs of shock veins may serve as one of the possibly few surviving indicators of impact metamorphism.

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Section: Discussionsupporting

confidence: 56%

Section: Discussionmentioning

confidence: 98%

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Investigating the response of biotite to impact metamorphism: Examples from the Steen River impact structure, Canada

Walton

Sharp

et al. 2017

Meteorit & Planetary Scien

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“…It is more likely that Tissint was launched in the higher-P and higher-T portion of the landing site of the impactor, with other shergottites of the similar CRE age being in proximal less-intense positions of the same crater (ref. 38). In such case, the high-P minerals and glasses of Tissint provide a better and more accurate estimation of the crater size as the potential source of the Shergottites.…”

Section: Discussionmentioning

confidence: 99%

The Tissint Martian meteorite as evidence for the largest impact excavation

et al. 2013

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“…The shock pressures on amphibolite in Ries crater were also estimated to be at 20–22 to 28–34 GPa (stage IIa) and 28–34 to 42–45 GPa (stage IIb), judging from occurrence of the shock veins [ Stöffler and Grieve , 2007]. Furthermore, Si contents of majorites in the shocked amphibolite give a deduction of shock pressure at ∼15–17 GPa and temperature at ∼2150–2230°C [ Stähle et al , 2011].…”

Section: Samples and Methodsmentioning

confidence: 99%

Shock barometer using cathodoluminescence of alkali feldspar

Kayama¹,

Nishido²,

Sekine³

et al. 2012

J. Geophys. Res.

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[1] Color cathodoluminescence (CL) images of unshocked and experimentally shocked sanidine at pressures up to 40.1 GPa showed red-violet emission below 20.0 GPa and blue emission above 20.0 GPa. The phases in these shock-recovered samples were identified as crystalline feldspar for red-violet emitting areas and as diaplectic feldspar glass for blue emitting ones by micro-Raman spectroscopy. CL spectra of these shocked sanidine have emissions at $330, $380 and 400-420 nm of which intensities increase with an increase in shock pressure. Similar UV-blue emissions were found in alkali feldspar and the glass in Martian meteorites and Ries crater impactite. The deconvolution of these CL spectra provides the emission component at 2.948 eV assigned to shock-induced defect center, where this intensity correlates linearly with peak shock-induced pressure on sanidine, with little dependence on composition and structure. The correlation gives quantitative values of the shock pressures experienced by the feldspar, resulting in estimated shock pressures of Martian meteorites and Ries crater impactite. The CL intensity of feldspar has a potential for a universal shock barometer with high spatial resolution ($1 mm) and in a wide pressure range (theoretically $4.5-40.1 GPa). This leads to a breakthrough in understanding the impact histories on Earth, Moon, and Mars.

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Ca-rich majorite derived from high-temperature melt and thermally stressed hornblende in shock veins of crustal rocks from the Ries impact crater (Germany)

Cited by 27 publications

References 60 publications

Investigating the response of biotite to impact metamorphism: Examples from the Steen River impact structure, Canada

Investigating the response of biotite to impact metamorphism: Examples from the Steen River impact structure, Canada

The Tissint Martian meteorite as evidence for the largest impact excavation

Shock barometer using cathodoluminescence of alkali feldspar

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