Worldwide contacts - Service & Support

AMETEK Materials Analysis Division
Hadean age for a post-magma-ocean zircon confirmed by CAMECA’s Atom Probe Tomography
CAMECA LEAP zirconFebruary 2014: A recent article by John W. Valley in Nature Geoscience reports on atomic–scale mapping of radiogenic isotopes with Atom Pobe Tomography, confirming the accuracy of previous dating of Jack Hills zircons by SIMS.

The only physical evidence from the earliest phases of Earth’s evolution comes from zircons, ancient mineral grains that can be dated using the U–Th–Pb geochronometer. Zircons older than 4.3-Gyr old are extremely rare. The only four terrestrial zircons, all from the Jack Hills, Western Australia, were initially analyzed by using SIMS (Secondary Ion Mass Spectrometry). Some scientists hypothesized that this technique might give a false date due to poorly understood processes of intracrystalline Pb mobility.

A group of scientists from several universities, led by Dr. John Valley from the University of Wisconsin, performed further analysis with a CAMECA LEAP® 3D Atom Probe. Thanks to the LEAP’s unique capabilities for 3D mapping at atomic scale resolution, individual lead atoms were identified in the crystal, confirming that this zircon is indeed 4.4-Gyr-old – one of the oldest minerals on earth! John W. Valley and his colleagues thus close the time gap between the formation of the Earth– Moon system and the generation of Earth’s first continental crust at about 100 million years, by mapping the distribution of radiogenic isotopes within a single zircon grain with unprecedented precision!

For more information read the full article published online: 23 February 2014, DOI: 10.1038/NGEO2075) 

You may also visit the University of Wisconsin - Madison Dpt of Geoscience web page for rotating atom movies, pictures and further links.



instruments for research - metrology tools - applications - user publications - news - conferences - company - locations

Atom Probe Tomography (APT) - SIMS - EPMA - LEXES - ICP-MS - GD-MS - TIMS

© 2010-2016 AMETEK, Inc - CAMECA SAS. All Rights Reserved -
privacy - trademarks - sitemap