A5022827612- Geological and Geochemical Analysis
- Geochemistry and Geologic Mapping
- Electron and X-Ray Spectroscopy Techniques
- earthquake and tectonic studies
- High-pressure geophysics and materials
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Materials Characterization Techniques
- Geology and Paleoclimatology Research
- Radioactive element chemistry and processing
- Ion-surface interactions and analysis
- Geochemistry and Elemental Analysis
- Mineralogy and Gemology Studies
- Clay minerals and soil interactions
- Nuclear Physics and Applications
- Nuclear materials and radiation effects
- Crystal Structures and Properties
- Geological Studies and Exploration
- Rare-earth and actinide compounds
- Magnetic and transport properties of perovskites and related materials
- Cultural Heritage Materials Analysis
- Hydrocarbon exploration and reservoir analysis
- Iron oxide chemistry and applications
- Research Data Management Practices
- High Entropy Alloys Studies
- Shape Memory Alloy Transformations
ETH Zurich
2017-2024
Institute of Geochemistry
2023
Board of the Swiss Federal Institutes of Technology
2022
University of Colorado Boulder
2013-2020
University of Massachusetts Amherst
2010-2019
University of Colorado System
2014
University of Bern
2011
Universidad Iberoamericana
2008
Abstract The distribution of REE minerals in metasedimentary rocks was investigated to gain insight into the stability allanite, monazite and xenotime metapelites. Samples were collected central Swiss Alps, along a well‐established metamorphic field gradient that record conditions from very low grade metamorphism (250 °C) lower amphibolite facies (∼600 °C). In Alpine metapelites investigated, mass balance calculations show LREE are mainly transferred between allanite during course prograde...
Trace element micro-analysis has evolved steadily since the early days of EPMA, yet remains an extraordinarily challenging subject. The enhanced capabilities modern instrumentation, including use spectrometers with high X-ray collection efficiencies, brightness electron sources, and improved stability all contribute to our ability improve detection limits analytical spatial resolution. Along much software for data acquisition analysis, recent progress in EPMA made trace realm more accessible...
The effects of metamorphic reactions occurring during decompression were explored to understand their influence on the 40Ar–39Ar ages micas. Monometamorphic metasediments from Lepontine Alps (Switzerland) reached lower amphibolite facies Barrovian metamorphism related collision between European and African (Adria) continental plates. Mineral assemblages typically composed garnet, plagioclase, biotite, muscovite paragonite (or margarite) screened for petrological equilibrium, focus samples...
The development of controlled processes for continuous hydrogen generation from solid-state storage chemicals such as ammonia borane is central to integrating renewable into a clean energy mix. However, date, most reported platforms operate in batch mode, posing challenge controllable release, catalyst reusability, and large-scale operation. To address these issues, we developed flow-through wood-based catalytic microreactors, characterized by inherent natural oriented microchannels....
Abstract Electron microprobe trace element analysis is a significant challenge. Due to the low net intensity of peak measurements, accuracy and precision such analyses relies critically on background any pertinent interference corrections. A linear regression between two points selected at appropriate positions classical approach for electron probe microanalysis (EPMA). However, this neglects accurate assessment curvature (exponential or polynomial), presence interferences, hole in...
Abstract While much progress has been made in electron-probe microanalysis (EPMA) to improve the accuracy of point analysis, same level attention not always applied quantification wavelength-dispersive spectrometry (WDS) X-ray intensity maps at individual pixel level. We demonstrate that rigor traditional analysis can also be pixels maps, along with additional acquisition and quantitative processing procedures further accuracy, precision, mapping throughput. Accordingly, map should include...
Changes from effusive to explosive behavior are common during single eruptive events. However, in many cases these shifts recorded between distinct eruptions, separated by periods of volcanic repose. In the quiescent periods, magma chamber processes likely play a major role controlling style next eruption, modifying properties magmas. Crystallinity, viscosity, dissolved water content and saturation state melt among that can easily change repose, influence magmas eruption. Here, we focus on...
It has been recognized for several decades that REE-phosphates (monazite and xenotime) can grow during diagenesis low-grade metamorphism. Growth of REE-bearing accessory phases at conditions commonly involves pervasive fluid-rock interaction, dissolution detrital grains, transportation, precipitation REEs, typically facilitated by an increase in temperature. The occurrence REE-phosphate offers a rare opportunity to date crystallization/mineralization possibly fluid percolation.
Formation and subsequent modification processes of lower crust play important roles in evolution rheological models for continental lithosphere. In the last two decades, numerous xenolith studies have documented metasomatism mantle Rocky Mountain region North America. However, much less attention has been paid to whether what extent these may affected crust. We address nature timing hydrous alteration extant deep Proterozoic Colorado Plateau through a petrological geochronological study from...
Cobalt arsenide deposits associated with Neoproterozoic serpentinite in Morocco represent the highest-grade cobalt resource worldwide. Yet, genetic models for their origin remain controversial. We report here mineralogical and geochemical evidence arsenide-calcite mineralization at Bou Azzer to constrain temporal framework identify geodynamic trigger mechanisms. To this end, radiometric ages ore minerals are paramount understanding of deposit. New safflorite (CoAs 2 ) rhenium-osmium (Re-Os)...
Fluid exsolution in magmas is a process that, many silicic upper crustal reservoirs, starts at relatively low crystallinities (near liquidus), and precedes the precipitation of ore bodies, including pegmatites. As any magmatic system approaches its solidus, amount exsolved fluid phase increases becomes progressively dominant over melt, allowing local pressurization generation pegmatitic pods/dykes. Such bodies show several features that point to both hydrothermal environments, linking those...
Abstract The 300-km-long Redstone copper belt in the Mackenzie Mountains, Northwest Territories, Canada, is composed of a series sediment-hosted stratiform (SSC) deposits hosted Neoproterozoic fault-bounded intracontinental rift basins. Mineralization at Coates Lake, largest these deposits, concentrated within microbial laminite layers transition zone between underlying continental red beds River Formation and overlying marine carbonates Coppercap Formation. Disseminated cupriferous sulfides...
An unusual rare earth element (REE) mineralization occurs at a locality known as the "Rusty Gold" within anorogenic 1.4 Ga Longs Peak-St. Vrain monzo- to syenogranite Silver Plume-type intrusion near Jamestown, Colorado (U.S.A.). Irregular-shaped centimeter- decimeter-sized mineralized pods and veins consist of zoned mineral assemblages dominated by fluorbritholite-(Ce) in gray-colored core up 10 cm thick, with monazite-(Ce), fluorite, minor quartz, uraninite, sulfides. The zone is...
Abstract Beryl from Xuebaoding, Sichuan Province, western China is known for its unusual tabular habit and W–Sn–Be paragenesis in a greisen-type deposit. The crystals are typically colourless transparent to pale blue, often with screw dislocations of hexagonal symmetry on the (0001) crystal faces. Combining electron microprobe analyses laser ablation inductively coupled plasma mass spectrometry single-crystal X-ray diffraction (XRD), correlated Raman micro-infrared (IR) spectroscopy imaging,...
Journal Article Trace Element Analyses by EMP: Pb-in-Monazite and New Multipoint Background Method Get access Julien Allaz, Allaz University of Colorado Boulder, Dept. Geological Sciences, Boulder (CO), USA Search for other works this author on: Oxford Academic Google Scholar MJ Jercinovic, Jercinovic Massachusetts Amherst, Geosciences, Amherst (MA), ML Williams, Williams JJ Donovan Oregon, CAMCOR, Eugene (OR), Microscopy Microanalysis, Volume 20, Issue S3, 1 August 2014, Pages 720–721,...
The exsolution of a magmatic volatile phase in the plumbing systems volcanoes plays key role controlling growth dynamics subvolcanic reservoirs and eruptive styles. By using common petrological proxies found volcanic deposits, such as melt inclusions apatite crystals, presence an exsolved can be traced, specifically water from silicate melt. To monitor variations saturation state magmas Aso complex (Kyushu, Japan) prior to during catastrophic Aso-4 caldera-forming event (at ∼86 ka BP), we...
As the most abundant solid phase at depths of 410–525 km, wadsleyite constitutes a large geochemical reservoir in Earth. To better understand implications minor element substitution and cation ordering wadsleyite, we have synthesized wadsleyites coexisting with pyroxenes 2–3 wt% either TiO2, Cr2O3, V2O3, CoO, NiO, or ZnO under hydrous conditions separate experiments 1300 °C 15 GPa. We refined crystal structures these by single-crystal X ray diffraction, analyzed compositions electron...
Minor and trace elements analysis by electron microprobe (EMP) requires a long counting time at high beam current (≥50-100 nA) in order to increase precision.The challenge is usually the accuracy, which depends essentially on correctness of background peak interference corrections [1,2].Such an becomes more challenging sensitive materials, like carbonate, phosphate, glass, alkali-rich due damage induced dose.As latter can yield (very) inaccurate results if not properly accounted for, it...
New electron microprobe analyses of Sr and Ba in feldspars coexisting experimental glasses show very strong correlations the partition coefficients with ternary Or content feldspar. The therefore scale inversely temperature, as also found literature. is maximized mesoperthite decreases evolution feldspar to minimum. relationship DSr/L decreasing XAn initially flat at a value 1.8 but curves sharply upward past 6.5 after arrival apatite An38. A similar concave-up curve much higher values D...