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Showing 1 to 8 of 8 for “"prehnite"”.
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Prehnite at the Atomic Scale: Al/Si Ordering, Hydrogen Environment, and High-Pressure Behavior
The mineral prehnite, Ca2(Al,Fe,Mn)(AlSi3O10)(OH)2, is a layered structure consisting of double-sheets of (Al,Si)O4 and SiO4 tetrahedra alternating with single sheets of AlO4(OH)2 octahedra. To understand the ordering in the structure and differences between various samples of prehnite, …
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Petrologic studies of the Robles Formation, south central Puerto Rico
… sericite; (2) laumontite and albite; (3) prehnite; (4) pumpellyite; (5) epidote; (6) actinolite. Assemblages containing analcime, celadonite, and laumontite belong to the zeolite facies of metamorphism. Remaining assemblages belong to the prehnite-pumpellyite facies. Secondary mineralogy …
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A single-crystal EPR study of radiation-induced defects in selected silicates
… silicate minerals, including apophyllites, prehnite, and hemimorphite, not only providing new insights to mechanisms of radiation-induced damage in minerals but also having direct relevance to remediation of heavy metalloid contamination and nuclear waste disposal. The NH2 free radical, …
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The Geochemistry of Silica in Icelandic Geothermal Systems
… whereas, at temperatures >230 °C feldspars, prehnite and epidote together with quartz are often most important. Geothermal geothermometry relies on the assumption of such fluid-mineral equilibria, that are in turn primarily dependent on the temperature at geothermal conditions. It follows, …
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Deciphering the signature of fluid/rock reactions in the lower oceanic crust: The Oman ophiolite analogue
… facies conditions and continued down to prehnite-pumpellyite facies. However, the textural characteristics of amphibole-rich fault zones imply an earlier, high temperature stage of deformation. The 87Sr/86Sr and δ18O values of the whole rocks and mineral separates point to formation from …
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Petrological and geochemical study of spilites and associated dike rocks from the Virgin Island core (Caribbean Island arc)
… the core and caused. the disappearance of prehnite and pumpellyite with depth.</p> <p>The parental magma of the spilite is believed to be derived from the partial melting of amphibolite tapped in the lower Crust or upper Mantle (extrapolated from experimental data) beneath the Virgin …
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An investigation of a polymetamorphic terrain using <sup>40</sup>Ar-<sup>39</sup>Ar geochronology
… was interlayered with chlorite, clinozoisite and prehnite but using the UV laser it was possible to separately analyse areas of unaltered biotite and areas of alteration within a single mineral and produce ages from both. It was thus possible to measure two ages from one sample: an unaltered age …
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Blueschists and associated rocks in the south Sepik region, Papua New Guinea; field relations, petrology, mineralogy, metamorphism and tectonic setting
… the Salumei Formation is metamorphosed from prehnite-pumpellyite to low-greenschist grade. Stratigraphic constraints and isotopic dating indicate an Oligocene to early Miocene metamorphism of the Tau Blueschist, Salumei Formation, and other metamorphic rocks in the region. The blueschists are …