NWA-2364 Contains Oldest Dated Calcium-Aluminum Inclusion

T. Bunch and J. Wittke, Northern Arizona University

Northwest Africa 2364

The image below shows the repository piece of the CV3 carbonaceous chondrite in which the ASU team of A. Bouvier and M. Wadhwa found the oldest known material in the solar system (4.568 billion years). This CV3 chondrite contains the typical collection of chondrules, calcium-aluminum inclisions (CAIs), fragments, and fine-grained matrix known in CV3 meteorites, in addition to probable carbonaceous compounds and interstellar nanodiamonds. NWA is moderately weathered and shocked with a total known weight of 1493 g. The scientific abstract of the ASU team's work is located at http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo941.html. A layman's description of this research is available at the Science Daily site.


Image of a cut surface of the NAU NWA-2364 carbonaceous chondrite that contains among other materials, interstellar abiotic organic compounds and nanodiamonds and the calcium- aluminum-rich inclusion (CAI) from which the ASU team extracted the oldest isotopic age (14 mm size gray object, arrow). Small spheres are chondrules, condensates from the early solar system.

CV3 Chondrites

CV3 chondrites are a meteorite class named after the Vigarano meteorite that fell in Italy in 1910 and closely resemble ordinary chondrites. CV3s have abundant large, well-defined chondrules of magnesium-rich olivine (>0.7 mm diameter; 40-65 vol. %), often surrounded by Fe sulfide. They also contain 7-20 vol. % CAIs. The dark-gray matrix is dominated by Fe-rich olivine (~60 vol. %). The Allende meteorite is a very famous and well-studied CV meteorite. As of August 2010, 176 CV3 meteorites are known of the ~52,000 recovered meteorites on Earth.