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A ‘ring’ agglutinate - formed by a single a micrometeor impact. There is a huge amount of energy associated with a micrometeor impact which can cause the underlying rock and soil (regolith) to melt. Some of the molten regolith then flows into the spaces between the surrounding lunar soil particles and as it cools it encases these particles in a vesicular glass matrix. The vesicles in the matrix have formed by the evolution of solar wind implanted gases as the temperature rose which have then become trapped in the viscous melt.