LUNAR VOLCANOES
Small, but widespread volcanoes discovered on the moon's surface could rewrite its volcanic history. NASA/GSFC/Arizona State University

In what could be a new chapter on the moon's volcanic history, scientists from the Arizona State University have discovered small, but widespread volcanic eruptions on the moon as recent as 50 million years ago.

Most of the lava flows that make up the dark plains on the moon visible by eye from Earth erupted between 3.5 and one billion years ago.

The geologically recent eruptions now discovered will drastically change our understanding of the moon, the team believes.

Using high-resolution images from Nasa's Lunar Reconnaissance Orbiter spacecraft, they identified 70 small volcanic features scattered across the moon's dark volcanic plains, or maria.

A combination of smooth, low, rounded mounds near patches of rough, blocky terrain, the features are referred to by scientists as irregular mare patches.

The ages of the irregular mare patch features come from studies of crater sizes and numbers within a given area. The results show that lunar volcanism ended gradually, continuing until less than 50 million years ago.

"The existence and young age of the irregular mare patches provides a new constraint for models of the lunar interior's thermal evolution," Sarah Braden, the lead author said. "The lunar mantle had to remain hot enough for long enough to provide magma for the small-volume eruptions."

The features are small averaging less than 500 metres across their largest dimension. One feature named Ina has been known for a long time, having been imaged from lunar orbit by Apollo 15 astronauts in the 1970s.

While it was indicated even earlier that Ina could be very young (10 million years or less), its significance was unclear as other features had not been detected.

Volcanic activity at Ina ended about 33 million years ago, but at another mare patch, Sosigenes, it stopped only about 18 million years ago, the recent discovery reveals.

The findings have been published online in Nature Geoscience.

The "man on moon" was recently shown by an MIT study to be the result of lava outpourings.

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