New research from the University of Bristol has revealed the origin of titanium-rich basaltic magma on the Moon.
A map of titanium abundance on the moon's surface from NASA's Clementine spacecraft. The red area shows a very high concentration compared to terrestrial rocks. Image credit: Lunar and Planetary Institute.
The presence of surprisingly high concentrations of the element titanium (Ti) on parts of the moon's surface has been known since NASA's Apollo missions back in the 1960s and 1970s. The mission successfully recovered samples of solidified ancient lava from the moon's crust.
Recent maps from orbiting satellites show that these magmas, known as titanium-rich basalts, are widespread on the moon's surface.
Professor Tim Elliott and colleagues at the University of Bristol have used advanced isotopic analysis of lunar samples in a series of high-temperature lava labs to identify key reactions that control the composition of these characteristic magmas.
This reaction occurred about 3.5 billion years ago deep inside the moon, replacing elements of iron in the magma with elements of magnesium in the surrounding rock, changing the chemical and physical properties of the melt.
“The origin of the Moon's volcanic rocks is a fascinating story involving an 'avalanche' of unstable, planetary-scale piles of crystals produced by the cooling of a primordial magma ocean,” Professor Elliott said.
“Central to this epic history is the presence of a type of magma unique to the Moon, which explains how such magma reached the surface to be sampled on space missions. It was a tricky problem to solve. I'm really glad we were able to resolve this dilemma.”
“Until now, models have not been able to reproduce magma compositions that match the essential chemical and physical properties of high-titanium basalts,” said Dr. Martin Claver, a researcher at the Institute of Mineralogy at the University of Münster.
“Explaining that low density made eruptions possible about 3.5 billion years ago has proven particularly difficult.”
“We successfully mimicked high-titanium basalts in a laboratory process using high-temperature experiments,” the researchers said.
“Measurements of the titanium-rich basalts also revealed a unique isotopic composition, a signature of reactions that were reproduced in experiments.”
“Both results clearly demonstrate how melt-solid reactions are essential to understanding the formation of these unique magmas.”
of findings Published in today's diary natural earth science.
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M. Claver other. Titanium-rich basaltic melts exist on the lunar surface, conditioned by reactive flow processes. nut.earth science, published online on January 15, 2024. doi: 10.1038/s41561-023-01362-5
Source: www.sci.news
