Unusual meteorite found in South Africa
During drilling in the Morokweng crater in South Africa, researchers have found a 25 centimeter large fossil meteorite. Together with other, much smaller remains, it apparently belongs to the object that created the crater 145 million years ago. However, its chemical composition distinguishes it from other meteorites of the same group.
Wolfgang Maier from the University of Québec and his colleagues discovered the boulder in a drill core from a depth of 766 meters. Smaller remains of less than a centimeter in diameter were found mainly between 300 and 400 meters deep. So far, the scientists have not been able to explain why traces of the original asteroid are still present at all - with similarly steep impact angles and high speeds, the extraterrestrial rocks usually melt and sometimes completely evaporate.
Except for a thin outer layer, the specimen appears geochemically unchanged. Although chemically reminiscent of a chondrite, its above-average iron-rich silicates distinguish it from comparable meteorite finds. Maier and his colleagues therefore suspect that the chunk reflects a previously unknown component of asteroid populations. Whether this is due to a temporary change in their chemical composition in general or the meteorite from Morokweng Crater comes from a different asteroid population can only be clarified by the discovery of further remains, the researchers say.