Asteroidal Lava Flows
نویسنده
چکیده
Some meteorites are pieces of lava flows. They have the expected minerals present and the crystals are intertwined in a characteristic way indicative of crystallization in a lava flow. This shows that lavas erupted on at least some asteroids. Age dating indicates that the eruptions took place 4.5 billion years ago. Planetary scientists have recognized three main groups of asteroidal lava flows, each distinctive enough to show that they must come from different asteroids. The most abundant are the eucrites, which might actually hail from asteroid 4 Vesta. Mesosiderites are complex mixtures of smashed up volcanic rock and metallic iron. Angrites have a distinctive group of minerals in them, but also clearly formed by volcanism. Recent studies increase the number of groups to five.
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