Iron meteorites and paradigm shifts

The assumption that iron meteorites were formed by planetary differentiation of asteroid-scaled parent bodies is deeply imbedded in the standard solar system formation model. This assumption is directly falsified by the trace element distributions in one significant group of iron meteorites and is not supported by chronologic studies of primordial or extinct radioisotopes. There is growing evidence that iron meteorites may be individually and, as a class, isotopically heterogeneous. The paradigm of iron meteorite formation is undergoing a fundamental shift.