Origin of BeLaU-type spherules

Determine the planetary or astrophysical origin of BeLaU-type spherules exhibiting highly differentiated, evolved compositions with extreme refractory lithophile enrichment and volatile depletion, which are unlike known solar-system materials.

Background

The BeLaU subset (approximately up to ~10% of the collection) displays distinctive elemental patterns, including very high CI-normalized refractory lithophile abundances and low volatile elements, with magnetite/spinel rims indicative of rapid quenching. Comparative analyses suggest lunar KREEP is the closest known pattern, yet significant differences remain.

The authors explicitly state that these spherules have an unknown origin, raising fundamental questions about possible magma-ocean processes, differentiated planetary sources, or extra-solar provenance. Establishing their origin is critical to interpreting IM1-related sampling and to broader cosmochemical understanding.