Lab
High-precision U-Pb dating of accessory minerals
We have many years of experience with U-Pb geochronology of accessory minerals in magmatic and metamorphic systems (e.g., zircon, apatite, monazite, rutile, titanite, perovskite, baddeleyite). State-of-the-art procedures include chemical abrasion of zircon, single and double-isotope tracer (ET535, ET2535) for both Pb and U isotope analysis, allowing us to correct for isotope fractionation online, lowest procedural Pb blanks of 100-200 femtograms, leading to an age resolution of ± 150'000 years for a single analyses, and ± 40'000 years for a cluster of 4 points. The infrastructure consists of:
a) Lowest-blank clean room facility (class 100) for isotope analysis of accessory minerals (single grains), used for the chemical preparation of mineral grains for high-precision U-Pb geochronology, trace element and Hf isotope analysis. Quality assessment is carried out by repeated analysis of Earthtime synthetic solutions (ET100, ET500, ET2000) as well as zircon reference materials, such as Plesovice, Temora, R33, GJ-1 and others.
b) Thermal Ionization Mass Spectrometer Finnigan TRITON (installed in January 2006) is mainly used for high-precision U-Pb dating of zircon (plus other U-rich minerals). It is equipped with 9 Faraday cups, 1 discrete-dynode SEM, and an arrangement of 6 channeltron ion counters for Os isotopic analyses. The Faraday cups can be connected to amplifiers with either 1011Ω (n=5) or 1013Ω (n=5) resistors, the upgrade to the 1013Ω resistors dates from 2018.
c) Thermal Ionization Mass Spectrometer - Isotopx PHOENIX, purchased in 2016, is optimised for high-sensitivity U-Pb geochronology. It is equipped with ATONA faraday cups and a Daly-based ion-counting system using a Hamamatsu photo-multiplier, demonstrated to be linear up to 2.5 Mcps.
For information please contact :
Maria Ovtcharova, Phone: +41 22 37 96600 Email
High-precision U-Pb dating of carbonates
U-Pb ID-TIMS analyses (Isotope dilution thermal ionization mass spectrometry) of minerals with low-uranium (<1 ppm) and variable lead concentrations are usually conducted following LA-ICPMS analyses. We work on 5 to 10 aliquots per sample in order to achieve variation in U/Pb and to be able to calculate an isochron in the Terra-Wasserburg concordia plot. For each aliquot a millimeter-sized chip or 0.5 to 4 mg powder of the material is carefully extracted using a micro drilling device. We use EARTHTIME 205Pb-233U-235U tracer and process the sample via two steps modified HBr anion exchange chromatography to separate Pb and U from other elements. We measure the isotopic ratios on either the Thermo TRITON or the IsotopX mass spectrometers. Total procedural blanks measured at UNIGE are usually low, yielded an average of 1.15 pg. Data reduction and uncertainty propagation are performed using Tripoli and an Microsoft Excel-based spreadsheet that uses the well-established algorithm in the U-Pb dating community.
For information please contact :
Maria Ovtcharova, Phone: +41 22 37 96600 Email
High-precision U-Th dating of carbonates
The U-Th lab at UNIGE will be constructed in September 2024. We follow standard column separation procedure for the extraction of U and Th fractions from bulk sample. To ensure minimal blank corrections during this step, we work in a clean and safe lab environment using a metal-free laminar flow-boxes with automated control on airflow and ventilation to protect for samples contamination while ensuring user safety. We will also work with a prepFAST system, designed specifically for automated U and Th column-chemistry separation, and helps working with large number of analyses.
For information please contact :
Perach Nuriel, Phone: +41 22 37 96611 Email
Isotope analysis (Neptune Plus MC-ICPMS)
Neptune Plus MC-ICPMS equipped with (APEX Ω) aspirating systems, currently used for isotopic analysis of both solutions (Pb, Sr, Nd, Cu, Zn, Fe, Hf from bulk dissolved rock samples and single zircon grains) and laser-ablated aerosols (coupling with a NWR-193 HE laser ablation system of the Mineral Resources and Geofluids Group of Prof. Z. Zajacz). The MC-ICPMS has specific configuration for U and Th isotopes measurements and will be used for future U-Th geochronology (Prof. P. Nuriel).
For information please contact :
Massimo Chiaradia, Phone: +41 22 37 96634 Email
Isotopic tracing laboratory for the separation of various elements (clean lab)
A clean laboratory for the separation of Sr, Nd, Pb, Cu, Zn and Fe from various matrices (both solid and fluid).
For information please contact :
Massimo Chiaradia, Phone: +41 22 37 96634 Email
Gas source mass spectrometer (high sensitivity)
Argus VI with high gain Faraday detectors (1x1013 Ohm) and a single CDD multiplier, attached to a low volume, stainless steel extraction line equipped with an IR laser (Fusions 10.6 microns, Teledyne).
For information please contact :
Richard Spikings, Phone: +41 22 37 96634 Email
Gas source mass spectrometer (high resolution)
MC Helix with five Faraday detectors and five CDD multipliers, attached to a low volume, stainless steel gas extraction line equipped with an IR laser (Fusions 10.6 microns, Teledyne).
For information please contact :
Richard Spikings, Phone: +41 22 37 96634 Email
193nm excimer laser
193nm excimer laser (spot sizes 400 - <10 microns): G2 Analyte equipped with an x-y-z-theta aperture, used for in-situ Ar isotope measurements.
For information please contact :
Richard Spikings, Phone: +41 22 37 96634 Email
Fission track facility: Zeiss Axioimager Z1M
Fission track facility: Zeiss Axioimager Z1M
For information please contact :
Richard Spikings, Phone: +41 22 37 96634 Email
Mineral separation lab (heavy liquid, Wilfley table, magnetic Frantz)
Mineral separation lab (heavy liquid, Wilfley table, magnetic Frantz)
For information please contact :
Richard Spikings, Phone: +41 22 37 96634 Email
Micromill for microsampling (µg)
A Merchantek micromill for microsampling of solid materials (e.g., minerals and fossils). Microanalysis in general and for U-Th dating are done on small size powder samples (‘bulk analysis’) that are physically separated from small microstructures with estimated weight of 1-3 mg of each sub-sample. To improve textural control, resolution, and accuracy we use thin-section billet to correlate micro-drilled samples with growth texture and CL/XPL/PPL imaging. We use the micromill system, designed especially for texturally complex samples, to allow for up to 1 mm resolution and potential dating of thin growth phases while avoiding mixing with other phases.
For information please contact :
Massimo Chiaradia, Phone: +41 22 379 6634 Email
Cathodoluminescence lab
We study the microstructures of samples including, thickness, grain size, mineralogy, morphology, growth texture, luminescence, zoning, and post formation deformation (shearing direction, twins-morphology in carbonate etc.) and alteration. We use cathodoluminescence instrument of New Tec with automated stage to image the whole thin section. Together with XPL and PPL imaging we can constrain the growth mechanisms and differentiate between growth phases and identify zoning, mixing, and potential dissolution and reprecipitation processes.
For information please contact :
Perach Nuriel, Phone: +41 22 37 96611 Email
