Topic
Incompatible element
About: Incompatible element is a research topic. Over the lifetime, 2420 publications have been published within this topic receiving 154052 citations.
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01 Jan 2010
TL;DR: In this paper, a field-based study on the evolution of alkaline to peralkaline rocks from the Mont Saint-Hiliaire complex, Quebec, Canada, is presented.
Abstract: Summary We present details of a field-based study on the evolution of alkaline to peralkaline rocks from the Mont Saint-Hiliaire complex, Quebec, Canada. The progressive magmatic evolution of the complex is represented by three melt batches: (1) primitive gabbroic rocks (XFe cpx = 0.17-0.27, where XFe cpx = molar Fetot/(Fetot+Mg)), (2) a dioritic/monzonitic rock suite (XFe cpx = 0.17-0.41) and (3) highly evolved peralkaline foid syenites (XFe cpx = 0.28-1). Nd and oxygen isotope data as well as major and trace element analyses of mineral separates indicate that all rock units derive from a single mantle source presumably by fractional crystallization processes from one parental melt. Solidification in the orthomagmatic stage probably occured under closed-system conditions. In the highly evolved peralkaline foid syenites, a wealth of minerals is found in the Poudrette quarry, which made Mont Saint-Hilaire a world-famous mineral locality. The late-stage evolution and formation of these partly exotic and rare minerals was reconstructed using a combination of stable isotopes of late-stage carbonates and comprehensive fluid inclusion studies. To explain the wealth of different minerals, at least two sources are necessary: (1) a mantle-derived and fractionated melt of alkaline character. Such magmas are strongly enriched in incompatible elements such as HFSE and LILE. (2) External fluids, probably in equilibrium with surrounding sedimentary rocks. The influence of this external fluid source is detected by the late-stage carbonate minerals’ O and C stable isotope composition, which displays a mixing trend between typical mantle values and sedimentary host rock limestone. Therefore, mixing of these external fluids with the restitic magma and/or its exsolved fluids caused dissolution and re-precipitation processes, resulting in the formation of a large number of rare and exotic minerals.
TL;DR: In this paper, the covariance relationship between compatible and incompatible elements is analyzed in the context of fractional crystallization, batch melting and magma mixing, and it is shown that compatible elements are correlated with compatible elements.
Abstract: On the basis of the previous quantitative modelling of trace element behavior in magmatic processes such as fractional crystallization, batch melting and magma mixing, the author has shown the covariance relationship between compatible and incompatible elements.
01 Jan 2007
TL;DR: In this paper, isotopic compositions for basalts recovered from the fossilized AntarcticPhoenix Ridge (APR) in the Drake Passage, Antarctica, in order to understand the nature of sub-ridge mantle source were determined.
Abstract: Summary We determined Sr, Nd and Pb isotopic compositions for basalts recovered from the fossilized Antarctic-Phoenix Ridge (APR) in the Drake Passage, Antarctica, in order to understand the nature of sub-ridge mantle source. Enriched (E-type) mid-ocean ridge basalts (MORB) coexist with the normal (N-type) MORBs in the axial region of the APR, being far from any known hotspots. The E-type basalts are relatively young in comparison with the N-type samples, and erupted after the extinction of the APR. Extent of enrichment in incompatible elements in the basalts correlates positively with isotopic ratios of Sr and Pb, and negatively with Nd. The E-type melts have been generated by low-degree of partial melting of an enriched mantle source. Extinction of the APR is likely to lead the extent of partial melting in this region to decrease. We interpret that the geochemically enriched materials might exist as a form of highly localized spots or veins in ambient depleted mantle of this region, and have been the first fraction to melt for generating the E-type basalts studied.
TL;DR: In this paper, the authors present data on isotope, volatile and incompatible element composition of Kamchatka ultramafic melts and discuss the geochemical aspects of their genesis.
Abstract: Late Cretaceous ultramafic volcanics from Eastern Kamchatka (Russia) occur as pillowlavas, tuffs, dykes and sills, associated with basalts within tectonic blocks, namely Valaginsky (VR) and Tumrok (TR) ranges (Sobolev et aL, 1990; Kamenetsky et al., 1993). Picrites and basalts form a suite, genetically related to islandarc tectonic setting and characterised by elevated KzO (1-4 wt.%) and K20/Na20 (0.8-1.3) typical of shoshonite affinities. The rocks being unusually enriched in olivine phenocrysts (35-65 %) possess very high MgO contents (20-40 wt.%). The exceptionally primitive composition of the phenocryst assemblage (olivine Foss-95, Cr-spinel Cr# up to 85 mol.%) unambiguously evidences the mantle origin of primary melts and their highmagnesian composition (MgO 19-24 wt.%), which has been confirmed by heating-stage study of melt inclusions in phenocrysts and thermodynamic modelling. The petrological study revealed the physical parameters of formation of primary melts, which are high pressure (30-50 kb) and temperature (1500-1700~ Here we present data on isotope, volatile and incompatible element composition of Kamchatka ultramafic melts and discuss the geochemical aspects of their genesis.