Volcanic 'face' on the Moon developed over 4 billion years ago

Washington, Dec 6: A scientist of Indian origin is part of a new study based on a moon rock, which indicates that volcanoes, that are visible from Earth and resemble a face on the surface, developed on the moon soon after its formation, leading to new information about how planets develop in their early stages.
The 30-pound (13.5-kilogram) moon rock was found in the Kalahari Desert in Botswana in 1999.
"It seems like it came upon Earth relatively recently, unlike many lunar meteorites," team member Mahesh Anand of Open University in Milton Keynes, England, told National Geographic News.


"The meteorite landed on Earth about 200 to 300 years ago," said Anand. "It was probably blasted free from the moon when an asteroid hit the lunar surface," he added.
But the Kalahari meteorite is made of basalt, a common rock that forms from cooling magma, that is a telltale sign of volcanic activity.
According to Anand, the age of the rock suggested that volcanoes had already begun erupting just 150 million years after the moon's creation.
Earlier studies—based on rocks collected from the moon's surface during the Apollo missions between 1969 and 1972—suggested that the bulk of the moon's volcanic activity occurred after 3.9 billion years ago.
"Apollo-era research suggested that it took a long time for the moon's volcanoes to erupt," said Anand.
But the researchers came up with the new theory about volcanic formation on the moon after examining small grains of two phosphate-containing minerals—apatite and merrillite—inside the rock.
Once magma solidifies, it becomes closed like a time capsule, and its radioactive uranium begins to split into other elements. Measuring the ratios of these elements reveals the rock's age.
Using this process, it was proved that the Kalahari meteorite is made of magma that solidified 4.35 billion years ago, soon after the moon formed.
"So volcanism on the moon had started much earlier than we had thought," said Anand.
The new research also sheds rare light on the earliest stages of planet formation, which has largely been lost on Earth, where plate tectonics continually recycle the crust, sucking continents into the planet's interior and melting the rocks.
Because of this, even tiny bits of rock from early Earth are extremely scarce.
But since the moon is much smaller, it cooled quickly and never developed plate tectonics. Many of its ancient rocks are still on or near the surface.
"The beauty of the moon is that it preserves almost the entire history of the solar system," said Anand.
"The work is important because we are looking at the moon for a snapshot of what the early Earth was like," said Irene Antonenko, a geologist with Geosoft, a geology software company based in Toronto, Canada. (ANI)