Extract from introduction: Regolith breccias are breccias that contain solar-gas-bearing grains [1,2]. It is generally accepted that the exposure to the solar wind took place rather recently on the surface of a parent body. However, it appears possible that grains were exposed early (or obtained their solar gas load by other mechanisms) prior to accretion. Some of the solar gases in chondrites may indeed be 'primordial' [3,4]. In the CI chondrite Orgueil, the presence of solar gases is restricted to magnetite, whereas the silicates appear solar-gas-free [3]. This is difficult to reconcile in a planetary environment. The observation that solar-like gases in the unbrecciated E chondrite St. Mark's were released only upon severe etching provides further evidence for the presence of primordial solar gas [5]
