When Apollo astronauts landed on the Moon, preparing to face a lifeless wasteland, they were taken aback to find the surface covered in gleaming orange glass beads. Tiny grains, about as small as a pencil tip, are left over from giant volcanic eruptions more than 3.5 billion years ago. Those raindrop-shaped beads were made from molten droplets that spouted during blazing explosions and then cooled in the Moon’s frigid vacuum. Such glass beads are safe in the storms of the airless, sheltered moon. They have been reconsidered yet again with forward-leaning tools, and with them come brightly dramatised, violent graphical bullet points of a world that once was tropical and full of colour.
Moon’s Ancient Glass Beads Reveal Explosive Volcanic Past and Clues to Lunar Interior Evolution
As per a recent analysis published in Universe Today, a team of scientists from Washington University and elsewhere employed high-resolution electron microscopy and ion beam techniques to analyse the mineral content of Apollo-era samples that contain a well-preserved record of lunar volcanic eruptions and associated eruption style, temperature, and chemical environment.
The beads range in colour from shiny black to matte dull red and vibrant orange, and they show differing eruption and magma source conditions on the moon’s surface. Some papers demonstrate rapid lava cooling, while others indicate so-called magma residence time. The surfaces of the beads contain isotopic data, and that information holds clues to the Moon’s molten interior, dating 3.3-3.6 billion years ago, as it first started to develop.
It’s because each bead is a testimony not to a dramatic volcanic event that took place on the Moon, but with each bead, there’s a journal entry written about that event, long ago, back in the days of our lunar volcanologists. “If we can date when that volcanism happened, we can start to assemble the history of what the moon was oriented like, the history of it and what was happening,” he says, “not just in the moon, but it has implications for planetary history in general; we can do this elsewhere in the solar system.
The proposed instruments for NASA’s Artemis missions will continue to search the Moon and discover more bead samples and other sampling varieties and enable a better understanding of the lunar volcanic record, rewriting lunar geology and transforming scientific views of the history of the cosmos.
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