A Mass-balance Perspective on the Origin of Agglutinitic Glass
نویسنده
چکیده
Précis: Glass composition of individual agglutinate grain is determined largely by the composition of a few soil grains, heterogeneous with respect to the bulk soil, impacted by a micrometeorite. Common perception or consensus: Lunar agglutinates form upon micrometeoritic bombardment of lunar soils and consequent preferential melting of the (otherwise homogeneous) finer fraction, scavenging unmelted or partly melted soil grains, incorporating vapor deposited nanophase Fe, (autoreducing Fe in the melt using solar wind implanted hydrogen on grain surfaces, coagulating immiscible Fe in the silicate melt as globules), which quenches to produce a constructional soil grain [1-6] We propose and argue: Lunar agglutinates form upon micrometeoritic bombardment of lunar soils and consequent preferential melting of the immediate target – inhogeneous with respect to mineralogy and grain size but with the dominance of the finer fraction and modal mineralogy, scavenging unmelted or partly melted soil grains, incorporating vapor deposited nanophase Fe, autoreducing Fe in the melt using solar wind implanted hydrogen on grain surfaces, coagulating immiscible Fe in the silicate melt as globules of different sizes, which quenches to produce a constructional soil grain. Figures 1 and 2. Backscattered electron images of segments of two agglutinate grains in soils 15221; note size, abundance and patterns of concentration.
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