Properties and distribution of paired candidate stony meteorites at Meridiani Planum, Mars

Citation

Schröder C, Herkenhoff KE, Farrand WH, Chappelow JH, Wang W, Nittler LR, Ashley JW, Fleischer I, Gellert R, Golombek M, Johnson JR, Klingelhoefer G, Li R, Morris RV & Squyres SW (2010) Properties and distribution of paired candidate stony meteorites at Meridiani Planum, Mars. Journal of Geophysical Research: Planets, 115 (E7), Art. No.: E00F09. https://doi.org/10.1029/2010JE003616

Abstract
The Mars Exploration Rover Opportunity investigated four rocks, informally dubbed Barberton, Santa Catarina, Santorini, and Kasos, that are possible stony meteorites. Their chemical and mineralogical composition is similar to the howardite, eucrite, and diogenite group but with additional metal, similar to mesosiderite silicate clasts. Because of their virtually identical composition and because they appear to represent a relatively rare group of meteorites, they are probably paired. The four rocks were investigated serendipitously several kilometers apart, suggesting that Opportunity is driving across a larger population of similar rock fragments, maybe a meteorite strewn field. Small amounts of ferric Fe are a result of weathering. We did not observe evidence for fusion crusts. Four iron meteorites were found across the same area. Although mesosiderites are stony irons, a genetic link to these irons is unlikely. The stony meteorites probably fell later than the irons. The current atmosphere is sufficiently dense to land such meteorites at shallow entry angles, and it would disperse fragments over several kilometers upon atmospheric breakup. Alternatively, dispersion by spallation from an impacting meteoroid may have occurred. Santa Catarina and a large accumulation of similar rocks were found at the rim of Victoria crater. It is possible that they are associated with the impactor that created Victoria crater, but our limited knowledge about their distribution cannot exclude mere coincidence.

Keywords
impact; mesosiderite; meteorite accumulation

Journal
Journal of Geophysical Research: Planets: Volume 115, Issue E7

People

Dr Christian Schroeder

Senior Lecturer, Biological and Environmental Sciences