LA‐ICP‐MS Pb isotope test of meteorite provenance: A terrestrial origin for Lovina

1,2Christopher R. J. Charles,2,3Phil J. A. McCausland,2Donald W. Davis
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13492]
1TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 Canada
2Department of Earth Sciences, University of Toronto, 22 Russell St., Toronto, Ontario, M5S 3B1 Canada
3Institute for Earth and Space Exploration, Western University, London, Ontario, N6A 5B7 Canada
Published by arrangement with John Wiley & Sons

Lovina, classified as an ungrouped ataxite, is controversial and its identity as a meteorite has been questioned. In this work, we use Pb isotopes on targeted troilite nodules in Lovina as a test of its antiquity and provenance. Although precise ages cannot be obtained, LA‐ICP‐MS offers a rapid, straightforward procedure to establish the source of lead, whether ancient (meteoritic) or modern (terrestrial). For nine pristine, unweathered nodules in Lovina, we find a lead isotopic composition of: 206Pb/208Pb = 0.492 ± 0.003 (2σ, MSWD 0.79; 95%) and 207Pb/206Pb = 0.852 ± 0.003 (2σ, MSWD 1.09; 95%) with no detectable uranium. All lead compositions of the troilite fall in the range expected for modern environmental and mantle lead and are distinctly different from the primordial Canyon Diablo Troilite (CDT) composition of ancient meteoritic troilite. Although the origin of Lovina remains unknown, we conclude that lead in the Lovina troilite is unsupported by U decay and originated from a terrestrial source.

Discuss

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s