Econintersect: We earthlings tend to think of the moon as a cold, dead rock. However, the earth satellite may still have a partially fluid core and partially molten boundary layers. Such a description was published in the journal Science this year. Such a composition would obviously mean that the interior of the moon is quite hot. Scientific Computing has reported this week about a radioactive hot spot (C-B in graphic) existing on the surface of the far side of the moon, the face that is never visible from earth. The article refers to this “hot spot” as curious.From Scientific Computing:
Analysis of new images of a curious “hot spot” on the far side of the Moon reveal it to be a small volcanic province created by the upwelling of silicic magma. The unusual location of the province and the surprising composition of the lava that formed it offer tantalizing clues to the Moon’s thermal history.
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 bull’s-eye when the spectrometer data are projected onto a map, with the highest thorium concentration at its center.
Recent observations, made with the powerful Lunar Reconnaissance Orbiter (LRO) optical cameras, have allowed scientists to distinguish volcanic features in terrain at the center of the bull’s-eye. High-resolution three-dimensional 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.
Silicic volcanism produces high silicate rocks, such as granite. Basaltic volcanism contains much greater amounts of heavier metals and is the predominant form that volcanic activity has taken over the history of the moon. The volcanic center on the far side of the moon occurred relatively recently in geologic time and will cause geologists to reconsider the thermal evolution of the body, according to Bradley Jolliff, PhD, research professor in the Department of Earth and Planetary Sciences in Arts & Sciences at Washington University in St. Louis, quoted by Scientific Computing. Prof. Jolliff led the team that has conducted the research.