1,720,990 research outputs found
Trace element chemistry of high pressure minerals in prograde garnet lherzolites of the Central Alps.
No full textThe analysis of fluid+mineral inclusions in deeply subducted hydrous mantle: Implications for the genesis of trace element-rich supercritical fluids
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Garnet peridotites and pyroxenites from the Central Alps: an ion probe investigation on their high pressure minerals.
No full textIon probe trace element chemistry of high pressure minerals from peridotites of the Adula - Cima Lunga Unit (Central Alps).
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Pre-alpine extension recorded by deep gabbroic intrusions: evidence from the Fedoz metagabbro (Val Malenco, Italy).
No full textForward modeling of calc-silicate microinclusions and fluid evolution of a graphitic metapelite (NE Sardinia)
No full textThe primary microinclusion assemblage anorthite +/- margarite +/- epidote occurs within garnet and rutile in a graphitic metapelite from northeast Sardinia. The existence of the microinclusion assemblage and the observed paragenetic sequence and mineral compositions for the entire rock are in good agreement with phase relations predicted from thermodynamic data for the system CaO-Na2O-K2O-MgO-FeO-Al2O3-SiO2-TiO2-C-O-H. The complexity of the microinclusion phase relations is reduced by the specification of a component saturation hierarchy that permits thermodynamic projection through phases of variable composition. The microinclusion assemblage is predicted to be stable over the pressure and temperature intervals of 6585-6685 bars and 550-575-degrees-C, with a C-O-H fluid of composition X(o) = 0.46-0.57 (ca. 26-45 mol% CO2), where X(o) represents the atomic fraction of total O relative to O + H in the fluid phase. The assemblage anorthite + potassium feldspar + albite + muscovite + quartz, present within other garnets, requires an even more CO2-rich fluid composition with X(o) > 0.9 (ca. 89 mol% CO2). With progressive metamorphism, fluid composition was buffered toward more H2O-rich fluid compositions by the minute calc-silicate domains represented by the microinclusions. The CO2 fluid compositions represent a significant deviation from those generated by simple dehydration in the presence of graphite (X(o) = 1/3) and suggest that an additional source of O was contributed to the fluid, most probably as CO2. Because the buffering capacity of the calc-silicate domains would be overwhelmed by any significant fluid influx, an external source of CO2 is improbable. No internal source of CO2 is preserved, but the calcic character of the inclusions and the high-X(o) fluid compositions could be explained by carbonate in the metapelite protolith. The calc-silicate inclusions record an interval of the metamorphism during which low rates of fluid production and infiltration inhibited bulk equilibration. This interval was terminated by an episode of dehydration that introduced more voluminous quantities of fluid into the rock. These results suggest that fluid from adjacent rocks had not permeated the metapelite when the inclusions formed and provide an argument against the importance of pervasive fluid movement during a stage of the prograde metamorphism
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