Asteroidal source of L chondrite meteorites

Establishing connections between meteorites and their parent asteroids is an important goal of planetary science. Several links have been proposed in the past, including a spectroscopic match between basaltic meteorites and (4) Vesta, that are helping scientists understand the formation and evolution of the Solar System bodies. Here we show that the shocked L chondrite meteorites, which represent about two thirds of all L chondrite falls, may be fragments of a disrupted asteroid with orbital semimajor axis alpha = 2.8 AU. This breakup left behind thousands of identified 1-15 km asteroid fragments known as the Gefion family. Fossil L chondrite meteorites and iridium enrichment found in an approximate to 467 Ma old marine limestone quarry in southern Sweden, and perhaps also similar to 5 large terrestrial craters with corresponding radiometric ages, may be tracing the immediate aftermath of the family-forming collision when numerous Gefion fragments evolved into the Earth-crossing orbits by the 5:2 resonance with Jupiter. This work has major implications for our understanding of the source regions of ordinary chondrite meteorites because it implies that they can sample more distant asteroid material than was previously thought possible. (c) 2009 Elsevier Inc. All rights reserved.