Maralinga, a metamorphosed carbonaceous chondrite found in Australia

Open Access
Publisher Website
Google Scholar
Abstract
Abstract— The Maralinga meteorite was found near the village of Maralinga, South Australia (30°18′S, 131°16′E) in 1974, but was not recognized as a meteorite until 1989. One weathered individual was recovered with a total mass of 3.38 kg. The bulk composition and petrography of Maralinga indicate that it is a metamorphosed (petrographic type 4) carbonaceous chondrite with major similarities to the Vigarano‐subtype. However, recent trace element data from the literature suggest that Maralinga should be included with the CK (Karoonda‐type) carbonaceous chondrites. We classify Maralinga as an anomalous CK4 chondrite because of its abundant chondrules and refractory inclusions relative to other known members of the CK group. Maralinga contains homogeneous silicates, including Ni‐bearing olivines (Fa34), high‐Ca clinopyroxene, and rare orthopyroxene. Plagioclase is chemically heterogeneous and falls into two distinct compositional groups one of ∼ An20 and an ∼ An80 group. Highly oxidizing conditions during metamorphism of Maralinga are indicated by the abundance of magnetite and the paucity of Fe‐Ni metal.