Growth, replacement and element diffusion in metamorphic garnet revealed by trace element mapping 

2021 ◽  
Author(s):  
Daniela Rubatto ◽  
Lanari Pierre ◽  
Marcel Burger ◽  
Bodo Hattendorf ◽  
Gunnar Schwarz ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Major Elements ◽  
Element Distribution ◽  
Garnet Growth ◽  
Trace Element Distribution ◽  
Rock Interaction ◽  
Growth Zoning ◽  
Element Mapping

<p>Garnet is one of the most robust and ubiquitous minerals that record element zoning during crustal metamorphism. In addition to major element distribution, zoning in trace elements can provide a wealth of information to document the changing conditions of garnet growth and modification. Trace element distribution in garnet grains was mapped in 2D in thin section with laser ablation inductively coupled plasma time of flight mass spectrometry (LA-ICP-TOFMS) and conventional LA-ICP-MS to achieve a lateral resolution of 15-5 µm and limits of detection for the heavy rare earth elements (REE) down to 0.2 µg/g (Rubatto et al. 2020).</p><p>In granulite-facies garnet, major elements show diffusional resetting, whereas trace elements still largely document the growth history. Enrichment of trace elements in the garnet mantle is attributed to the consumption of biotite (V, Cr) and the dissolution of zircon (Zr) and monazite (Y+REE) in the coexisting melt. Lu is notably enriched in the garnet mantle with implications for geochronology. The gradual zoning of Y+HREE between mantle and core is reconcilable with diffusion over ~200 µm in 10 My at temperatures of 750–800°C</p><p>In amphibolite facies garnet, Y+REE trace element zoning closely matches the growth zoning in Ca with no notable diffusive modification. Y+REE zoning is dominated by Rayleigh fractionation in the core and in the outer zones it shows annuli that mark the sporadic breakdown of accessory phases.</p><p>Garnet in eclogite facies samples that underwent fluid-rock interaction show growth zoning in major and trace elements, with local oscillations and sectors. In certain samples, the overall distribution of REE can be reconciled with diffusion-limited uptake. Where garnet displays fluid-related veinlets, visible in major elements, that cross-cut the primary growth zoning, the regular Y+REE and Cr growth zoning is not affected by the veinlets. This indicates that the veinlets did not form by a crack-seal mechanism but are rather related to a selective replacement process.</p><p> </p><p><strong>References </strong></p><p>Rubatto D, Burger M, Lanari P, Hattendorf B, Schwarz G, Neff C, Keresztes Schmidt P, Hermann J, Vho A, Günther D (2020) Identification of growth mechanisms in metamorphic garnet by high-resolution trace element mapping with LA-ICP-TOFMS. Contrib Mineral Petrol 175:61 doi.org/10.1007/s00410-020-01700-5</p>

Methylmercury and Trace Element Distribution in the Organs of Stenella coeruleoalba Dolphins Stranded on the French Mediterranean Coast

2014 ◽  
Vol 8 (1) ◽  
pp. 35-48 ◽  
Author(s):  
Emmanuel Wafo ◽  
Véronique Risoul ◽  
Thérèse Schembri ◽  
Véronique Lagadec ◽  
Frank Dhermain ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Marine Pollution ◽  
Element Distribution ◽  
Mediterranean Coast ◽  
Trace Element Distribution ◽  
Slight Reduction ◽  
Stenella Coeruleoalba ◽  
Contamination Levels

The main objective of this study was to evaluate the contamination by mercury (Hg), methylmercury (Me-Hg), cadmium (Cd), selenium (Se), zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) in dolphins stranded on the French Mediterranean coast. The distributions of these contaminants in the organs of dolphins have also been studied. Overall, contamination levels varied according to the following sequence: liver > kidney > lung > muscle, except for cadmium (kidney > liver > lung > muscle). Size and sex of animals were also considered. Young dolphins were less impacted with trace elements than adults, except for copper. Among the studied parameters, the most important appeared to be the size of mammals. In addition, in the case of mercury and selenium, the sex of mammals seemed to be also relevant. The correlations between the concentrations of trace elements suggest the existence of detoxification processes. Since 1990s, using dolphins for tracing marine pollution, a slight reduction in the burden of the considered trace elements could be noted.

scholarly journals Trace-Element Distribution on Sulfide Mineralization in Trento Province, NE Italy

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 736
Author(s):  
Gianluca Bianchini ◽  
Claudio Natali ◽  
Paolo Ferretti ◽  
Lara Casagrande ◽  
Manuel Conedera ◽  
...  
Keyword(s):  
Trace Element ◽  
Middle Ages ◽  
Inductively Coupled Plasma ◽  
Analytical Data ◽  
Element Distribution ◽  
Trace Element Distribution ◽  
Sulfide Mineralization ◽  
High Concentration ◽  
Thin Sections ◽  
Local Soil

Sulfide mineralization in the province of Trento (northeastern Italy) includes various mineral assemblages that are often silver-rich and have been exploited in different phases from the Middle Ages until the 20th century. This study investigates mineralized rocks from three historically important sites (Calisio mount, Erdemolo lake, and the locality of Cinque Valli), providing new analytical data (Inductively Coupled Plasma-Mass Spectrometry on bulk rocks, and Scanning Electron Microscopy on thin sections) that demonstrate that parageneses do not only include galena, chalcopyrite, and sphalerite but also accessory minerals, such as tetrahedrite, tennantite, acanthite, and sulfosalts (matildite/polybasite). This explains the high content of As (up to 278 ppm), Bi (up to 176 ppm), and Sb (up to 691 ppm) that are associated with Pb–Cu–Zn mineralization. Notably, trace-element ratios indicate that, although closely associated from a geographical point of view, the studied sites are not genetically related and have to be referred to in distinct mineralization events, possibly induced by three diverse magmatic and hydrothermal phases that occurred in the Variscan post-orogenic setting. Besides geological and petrogenetic reconstruction, the new data outline potential geochemical risks, as they reveal a high concentration of elements characterized by marked toxicity that can be transferred into the local soil and water. Therefore, future studies should be devoted to better investigating the metal distribution in the surroundings of ancient mining sites and their geochemical behavior during the weathering processes.

Trace-element distribution in a garnet-chlorite rock from Foel Ddu, near Harlech, Merionethshire

1956 ◽  
Vol 31 (235) ◽  
pp. 319-327 ◽  
Author(s):  
P. A. Mohr
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Analytical Data ◽  
Element Distribution ◽  
Trace Element Distribution

SummaryAnalytical data on a garnet-chlorite rock and the contained garnet with spectrographic determinations of the trace elements are presented, and the principles determining the distribution of these elements between the garnet and the chlorite are discussed.

Trace element constraints on mid-crustal partial melting processes – A garnet ionprobe study from polyphase migmatites (Damara orogen, Namibia)

2009 ◽  
Vol 100 (1-2) ◽  
pp. 205-218
Author(s):  
C. Jung ◽  
S. Jung ◽  
E. Hellebrand ◽  
E. Hoffer
Keyword(s):  
Trace Element ◽  
Secondary Ion Mass Spectrometry ◽  
Element Distribution ◽  
Garnet Growth ◽  
Trace Element Distribution ◽  
Element Abundances ◽  
Diffusion Controlled ◽  
Gradual Variation ◽  
Secondary Ion

ABSTRACTTrace element abundances in garnet from a polyphase migmatite were measured by secondary ion mass spectrometry (SIMS) in order to identify some of the effective variables on the trace element distribution between garnet and melanosome or leucosome. In general, garnet is zoned with respect to REE, in which garnet cores are enriched by a factor of 2–3 relative to the rims. For an inclusion-rich garnet from the melanosome, equilibrium distribution following a simple Rayleigh fractionation is responsible for the decreasing concentrations in REE from core to rim. Inclusion-poor garnet from the same melanosome located in the vicinity of the leucosomes shows distinct enrichment and depletion patterns for REE from core to rim. These features suggest disequilibrium between garnet and the host rock which, in this case, could have been an in-situ derived melt. This would probably indicate a period of open-system behaviour at a time when the garnet, originally nucleated in the metamorphic environment reacted with the melt. In addition, non-gradual variation in trace element abundances between core and rim may suggest variable garnet growth rates. Inclusion-free garnet from the leucosome, interpreted to have crystallised in the presence of a melt, has a small core with high REE abundances and a broad rim with lower REE abundances. Here, crystal-liquid diffusion-controlled partitioning is a likely process to explain the trace element variation.

Partitioning of trace elements between garnet, clinopyroxene and diamond-forming carbonate-silicate melt at 7 GPa

2010 ◽  
Vol 74 (2) ◽  
pp. 227-239 ◽  
Author(s):  
A. V. Kuzyura ◽  
F. Wall ◽  
T. Jeffries ◽  
Yu. A. Litvin
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Element Distribution ◽  
Silicate Melt ◽  
Trace Element Distribution ◽  
Published Data ◽  
Trace Element Partitioning ◽  
Element Partitioning ◽  
Icp Ms ◽  
Melt Composition

AbstractConcentrations of trace elements in coexisting garnet, clinopyroxene and completely miscible carbonate-silicate melt (formed at 7 GPa from the Chagatai silicocarbonatite rock known to be diamondiferous) were determined using LA-ICP-MS. The partition coefficients for Li, Rb, Cs, Ba, Th, U, Ta, Nb, La, Ce, Pb, Pr, Sr, Nd, Zr, Hf, Sm, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb, Lu, Sc and Zn were determined. The new experimental data for trace-element partitioning between garnet, clinopyroxene and carbonate-silicate melt have been compared with published data for partitioning between garnet, clinopyroxene and carbonatite melt, and garnet, clinopyroxene and silicate melt. The results show that the trace-element partitioning is not significantly altered by changes in melt composition, with HREE always concentrated in the garnet. Carbonate-silicate melt, as a diamond-forming medium, and carbonatite or silicate melt equilibrated with mantle silicate minerals, behave similarly in respect of trace-element distribution.

scholarly journals Magnetic susceptibility and trace element distribution in compost size fractions .

2014 ◽  
Vol 4 ◽  
Author(s):  
Remigio Paradelo ◽  
María Teresa Barral
Keyword(s):  
Trace Elements ◽  
Magnetic Susceptibility ◽  
Trace Element ◽  
Anthropogenic Pollution ◽  
Element Distribution ◽  
Trace Element Distribution ◽  
Size Fractions ◽  
Trace Element Contamination ◽  
The Relationship ◽  
Distribution Of Trace Elements

Magnetic susceptibility can be used for assessing anthropogenic pollution in solid matrices, including soils and composts. This work studies the distribution of trace elements and magnetic susceptibility in the different size fractions of six composts, for the development of measures aimed at reducing compost pollution at the production stage. The results showed that magnetic susceptibility decreased with increasing particle size in all composts, and the same was true for most trace element concentrations. Magnetic susceptibility was significantly correlated with Fe, as well as with Cu, Zn, Pb, Cr and Ni, which proves the relationship between the presence of ferric particles and trace element contamination in compost. Our results suggest that the association of trace elements and magnetic susceptibility is a characteristic feature in municipal solid waste composts.

scholarly journals Relation between cathodoluminescence and trace-element distribution of magmatic topaz from the Ary-Bulak massif, Russia

2016 ◽  
Vol 80 (5) ◽  
pp. 881-899 ◽  
Author(s):  
Andrea Agangi ◽  
Arnold Gucsik ◽  
Hirotsugu Nishido ◽  
Kiyotaka Ninagawa ◽  
Vadim S. Kamenetsky
Keyword(s):  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Analytical Techniques ◽  
Trace Element Composition ◽  
Element Distribution ◽  
Trace Element Distribution ◽  
Clear Correlation ◽  
Cell Parameters ◽  
Near Ultraviolet ◽  
Stretching Vibration

AbstractIn order to define the cathodoluminescence (CL) properties of magmatic topaz and its relation with trace-element composition, we studied topaz phenocrysts from the Ary-Bulak ongonite massif, Russia using a wide array of analytical techniques. Scanning electron microscopy CL panchromatic images reveal strong variations, which define micrometre-scale euhedral growth textures. Several truncations of these growth textures occur in single grains implying multiple growth and resorption events. The CL-spectra of both CLbright and -dark domains have a major peak in the near-ultraviolet centred at 393 nm. Cathodoluminescence images taken after several minutes of electron bombardment show decreasing emission intensity. Electron microprobe analyses indicate high F concentrations (average OH/(OH + F) = 0.04 calculated by difference, 100 wt.% – total from electron probe microanalyses), consistent with what has been found previously in topaz-bearing granites, and the OH stretching vibration (∼3653 cm–1) was detected in Raman spectra. Laser ablation inductively-coupled plasma mass spectrometry traverses performed across the CL textures detected trace elements at ppm to thousands of ppm levels, including: Fe, Mn, Li, Be, B, P, Nb, Ta, W, Ti, Ga, light rare-earth elements, Th and U. Lithium, W, Nb and Ta appear to be correlated with CL intensity, suggesting a role for some of these elements in the activation of CL in topaz. In contrast, no clear correlation was found between CL intensity and F contents, despite the fact that the replacement of OH for F is known to affect the cell parameters of topaz.

scholarly journals Trace Element Distribution in Magnetite Separates of Varying Origin: Genetic and Exploration Significance

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 759 ◽  
Author(s):  
Demetrios G. Eliopoulos ◽  
Maria Economou-Eliopoulos
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Precious Metals ◽  
Trace Element Content ◽  
Element Distribution ◽  
Ore Deposits ◽  
Trace Element Distribution ◽  
Calc Alkaline ◽  
Porphyry Cu ◽  
Volcanic Source

Magnetite is a widespread mineral, as disseminated or massive ore. Representative magnetite samples separated from various geotectonic settings and rock-types, such as calc-alkaline and ophiolitic rocks, porphyry-Cu deposit, skarn-type, ultramafic lavas, black coastal sands, and metamorphosed Fe–Ni-laterites deposits, were investigated using SEM/EDS and ICP-MS analysis. The aim of this study was to establish potential relationships between composition, physico/chemical conditions, magnetite origin, and exploration for ore deposits. Trace elements, hosted either in the magnetite structure or as inclusions and co-existing mineral, revealed differences between magnetite separates of magmatic and hydrothermal origin, and hydrothermal magnetite separates associated with calc-alkaline rocks and ophiolites. First data on magnetite separates from coastal sands of Kos Island indicate elevated rare earth elements (REEs), Ti, and V contents, linked probably back to an andesitic volcanic source, while magnetite separated from metamorphosed small Fe–Ni-laterites occurrences is REE-depleted compared to large laterite deposits. Although porphyry-Cu deposits have a common origin in a supra-subduction environment, platinum-group elements (PGEs) have not been found in many porphyry-Cu deposits. The trace element content and the presence of abundant magnetite separates provide valuable evidence for discrimination between porphyry-Cu–Au–Pd–Pt and those lacking precious metals. Thus, despite the potential re-distribution of trace elements, including REE and PGE in magnetite-bearing deposits, they may provide valuable evidence for their origin and exploration.

Sign in / Sign up

Export Citation Format

Share Document