Criteria to distinguish terrestrial precursors from extraterrestrial micrometeorites

Determine whether enrichment of titanium and aluminum and rare-earth-element (REE) patterns can be used as reliable criteria for distinguishing spherules derived from terrestrial igneous precursors from micrometeorites of extraterrestrial origin.

Background

The paper reviews past use of Ti, Al enrichment and REE patterns to distinguish terrestrial from extraterrestrial spherules, but cautions that spherules from highly differentiated planetary bodies could show similar signatures to terrestrial materials. The authors explicitly state that it is not clear these criteria can differentiate origins robustly.

Establishing dependable discriminants is crucial for origin attribution, particularly for differentiated (D-type) spherules and the unusual BeLaU subset whose compositions deviate from common terrestrial and known meteoritic materials.