Implantation in Interplanetary Dust of Rare-Gas Ions from Solar Flares

Measurements of excess Ar(36) + Ar(38) ( released mainly at 1200 degrees C) in magnetic concentrates of Pacific sediments and in a dense concentrate of Greenland dust agree within an order of magnitude with expected concentrations implanted by solar-flare ion streams of energy less than 10 Mev per atomic-mass unit. The agreement implies that more than 10 percent of each concentrate may be extraterrestrial, depending on size distribution and flare spectra. Rare-gas measurements on fine-grained dust can provide data on: solar-flare "paleo-ion" fluxes, energy spectra, and isotopic abundances; identification, mineralogy, and chemistry of interplanetary dust; influx rates to Earth and sedimentation rates of oceanic cores; and lunar-surface residence and mixing times.