How moon rock formed 3.5 billion years ago

By Jim Leffman via SWNS

Moonrock was formed 3.5 billion years ago from magma type unique to the moon, scientists have revealed.

The presence of rocks, some dwarfing the astronauts who have stepped onto the lunar surface, has long perplexed geologists.

But researchers from the Universities of Bristol and Munster now believe they have found the origins of moon rock from samples brought back to Earth.

The team used a combination of high temperature lab experiments with molten rocks, together with sophisticated isotopic analyses of lunar samples to identify a critical reaction that controls their composition.

They discovered the rock was born deep in the lunar interior some three and a half billion years ago.

It involved exchange of the element iron in the magma with the element magnesium in the surrounding rocks, modifying the chemical and physical properties of the melt.

Co-lead author Tim Elliott, Professor of Earth Sciences at the University of Bristol, said: “The origin of volcanic lunar rocks is a fascinating tale involving an ‘avalanche’ of an unstable, planetary-scale crystal pile created by the cooling of a primordial magma ocean.

“Central to constraining this epic history is the presence of a magma type unique to the Moon, but explaining how such magmas could even have got to the surface, to be sampled by space missions, has been a troublesome problem. It is great to have resolved this dilemma.”

Their findings were published in the journal Nature Geoscience.

They discovered lunar magma known as ‘high-Ti (titanium) basalts’ to be widespread on the Moon.

Co-lead author Dr. Martijn Klaver, Research Fellow at the University of Münster Institute of Mineralogy said: “Until now models have been unable to recreate magma compositions that match essential chemical and physical characteristics of the high-Ti basalts.

"It has proven particularly hard to explain their low density, which allowed them to be erupted some three and a half billion years ago."

The international team managed to mimic the high-Ti basalts in the process in the lab using high-temperature experiments.

Their experiments revealed a distinctive isotopic composition that provides a fingerprint of the reactions reproduced by the experiments.