Tuesday, July 26, 2011

Volcanoes found on far side of the moon offer tantalising clues to its thermal history - 26th July 2011

New images have revealed a curious 'hot spot' on the far side of the moon to be a small volcanic province created by the upwelling of silicic magma, according to scientists.

The unusual location of the province, and the surprising composition of the lava that formed it, offer tantalising clues to the moon’s thermal history, they said.

The hot spot is a concentration of a radioactive element thorium sitting between the very large and ancient impact craters Compton and Belkovich that was first detected by Lunar Prospector’s gamma-ray spectrometer in 1998.

The Compton-Belkovich Thorium Anomaly, as it is called, appears as a bullseye when the spectrometer data are projected onto a map, with the highest thorium concentration at its centre.

Recent observations, made with the powerful Lunar Reconnaissance Orbiter (LRO) optical cameras, have allowed scientists to distinguish volcanic features in terrain at the centre of the bullseye.

High-resolution 3D models of the terrain and information from the LRO Diviner instrument have revealed geological features diagnostic not just of volcanism but also of much rarer silicic volcanism. Read More