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Join us at Goldschmidt “NANOSCALE GEOCHEMISTRY” event!

martes, junio 1, 2021

INVITATION

A Goldschmidt 2021 Workshop – on line

Organized by
Anne-Magali Seydoux-Guillaume, CNRS@LGL-TPE Lyon/Saint-Etienne, France
with the support of CAMECA.

NANOSCALE GEOCHEMISTRY:
an overview of recent Atom Probe Tomography applications to earth and planetary sciences.


Wednesday 7 July 2021
14.30 – 16.00 UTC+2


Denis Fougerouse - Curtin University, Australia
A new nanogeochronology approach for large-scale geological processes
The phosphate minerals monazite (REEPO4) and xenotime (YPO4) are widely used U-Th-Pb chronometers in the geosciences. Phosphate crystals often have micrometre to sub-micrometre textures which develop during (re)crystallisation, metamorphism, alteration, or deformation. However, resolving the timing of such small features can be challenging using conventional dating techniques. Atom probe tomography is the highest spatial resolution technique capable of isotopic measurements, and provides the opportunity to date minerals at an unprecedented scale. The analytical volume for atom probe data is typically <0.008 μm3, compared to a volume of >50 μm3 for secondary ion mass spectrometry analyses. In this contribution, we explore the analytical developments for phosphate nanogeochronology by atom probe microscopy. Through examples, we will illustrate the approach by studying the timing of radiogenic Pb mobility during large-scale geological processes.


Sandra Taylor - Pacific Northwest National Laboratory, USA

Resolving water incorporation in minerals via nanoscale defects
Nominally anhydrous minerals are capable of structurally-incorporating small amounts of hydrogen (H) as hydroxyl (OH) (colloquially referred to as water) within structural point defects and/or higher-dimensional defects, such as in planar defects and fluid inclusions. However, knowledge on the modes of incorporation is largely ambiguous due to the challenges in directly visualizing and characterizing water in the crystal structure at this scale. Thus, the ability to resolve water and related chemical constituents trapped in minerals at the atomic-scale has broad implications in geochemistry, from probing paleoenvironmental conditions to understanding the effect of water on mineral properties. We utilize atom probe tomography (APT) to map the distribution of water within nominally anhydrous minerals. APT is a powerful analytical technique enabling direct visualization of the elemental and isotopic distributions in three-dimensions, with sub-nanometer spatial resolution and part-per-million elemental sensitivity. Furthermore, it can potentially detect and map water within materials through its ability to resolve hydride species. The approach developed here can be applied to understand water incorporation mechanisms in minerals and its impact across various geological processes.

Lee White - The Open University, UK
Atoms to Planets: Using Atom Probe Tomography to Unravel the Secrets of the Solar System
Technological developments have enabled us to gain new insights into the formation and evolution of our Solar System, with sample return missions to Mars (Mars 2020), the Moon (Chang’e-5) and the asteroid belt (Hayabusa 2 and OSIRIS-REx) being complemented by the wider application of nanoscale techniques capable of maximising the scientific yield from returned materials. While a suite of correlative microscopic techniques (such as EBSD, TEM, and Raman) have offered insights into planetary processes, the emergence of atom probe tomography (APT) has allowed the generation of accurate chemical and isotopic analysis from unparalleled length scales. In this talk I will summarise the application of APT to meteoritic and returned materials, including lunar meteorite NWA 3163 and returned Apollo sample 78235, to underpin the importance of atom probe in the future analysis of planetary samples. In particular, the targeted analysis of characterised grains for U-Th-Pb analysis using APT offers unique insight into the timing of crust formation, evolution, and bombardment, yielding new insight into long running debates such as the timing and duration of a hypothesised period of late heavy bombardment on the Lunar surface.


Open to all Goldschmidt attendees!
Connection link available soon on CAMECA’s Goldschmidt virtual booth and on this page.

Mark your agenda and register now to receive the connection link in your mail box.

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