LUNAR VOLCANOES: This image from NASA's Lunar Reconnaissance Orbiter shows a region on the far side of the moon between the Compton and Belkovich craters. The colored region marks a high amount of the mineral thorium, which is thought to have been deposited by rare silicate volcanoes in the past.
Image: NASA/GSFC/ASU/WUSTL, processing by B. Joliff
Shielded from Earth-bound eyes, the far side of the moon is home to a rare set of dormant volcanoes that changed the face of the lunar surface, a new study finds.
Data and photos from NASA's Lunar Reconnaissance Orbiter (LRO) reveal the presence of now-dead silicate volcanoes, not the more common basaltic volcanoes that litter the moon's surface, researchers said.
"Most of the volcanic activity on the moon was basaltic," primary author Brad Jolliff of Washington University told SPACE.com in an email. "Finding other volcanic types is interesting as it shows the geologic complexity and range of processes that operate on the moon, and how the moon's volcanism changed with time." [Photos of the dormant far side moon volcanoes]
Searching the far side
Because the moon's rotation has been affected by tidal forces between Earth and the moon, only one side of the moon is visible from Earth. The far side of the moon—sometimes referred to inaccurately as the "dark side"—was hidden from view until 1959, when Soviet Union's Luna 3 spacecraft took the first photos of the region.
When NASA's Lunar Prospector probe circled the moon in 1998, it revealed a highly reflective plain lying between two ancient impact craters. Known as the Compton-Belkovich region, this part of the moon contains thorium and other silicate rocks, suggesting a more involved type of volcanic activity than that which created the moon's well-known dark plains of basaltic plains known as "maria," or "seas."
But it wasn't until the LRO captured higher-resolution images for the region could this volcanic activity be confirmed. The spacecraft found a number of domelike features with steeply sloping sides—telltale signs of lunar volcanoes.
Jolliff said that the domes likely formed by lava probably came from deep within the moon. It flowed upward through cracks to pool just beneath the surface, where it pressed out to form large domes.
Lava continued to work its way to the surface throughout the area, building other, smaller volcanic domes. Some areas then collapsed, creating the irregular depressions observed by LRO's camera, researchers said.
The research is detailed in the July 24 edition of the journal Nature Geoscience.
Rare volcanoes on the moon
Most volcanoes, on Earth and off, are near other volcanoes. But the grouping in the Compton-Belkovich region is isolated.
"This small volcanic complex occurs far away from the part of the moon where most of the volcanic activity was concentrated, and where other silicic volcanism occurred," Jolliff said. "That's a puzzle." [10 Coolest Moon Discoveries]
Older, defunct volcanoes are not themselves uncommon. Scientists have known for years that volcanoes on the moon filled in craters to form the dark maria visible from Earth's surface. However, those lava flows are basaltic in nature.
The team also used the Diviner Lunar Radiometer Experiment to confirm the type of rocks on the plain.
"Very few minerals have an infrared spectrum that can explain Diviner's observations of Compton-Belkovich and the other nonbasaltic volcanoes on the moon," study co-author Timothy Glotch of Stony Brook University told SPACE.com via email.
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7 Comments
Add CommentCould such natural domes be modified and made habitable for human use? They might provide an ideal biosphere for human habitation...
Reply | Report Abuse | Link to thisUsing lava domes for life support habitats sounded like a great idea, so I looked up "lava domes" the wikipedia.org. Not only was there no indication that lava domes are hollow, but one statement seemed to indicate that ordinary lava domes may not be habitable. It states that the "sides of these structures are composed of unstable rock debris."
Reply | Report Abuse | Link to thisThe real candidate for underground habitation is the lava tubes, some the width of super guppies or greater. These structures are often stable and impervious to meteor impacts.
You may be right because the Moon's low gravity may cause its lava domes to become hollow and produce a more stable dome structure, but that's speculation.
"sides of these structures are composed of unstable rock debris."
Reply | Report Abuse | Link to thisI'm curious. When, exactly, did the Wikipedia authors tour the lava domes on the far side of moon?
Seriously, how could they possibly know about lava flows in a vacuum? Polaroid pictures from their extensive field expeditions? See?
Be careful who your experts are.
Actually I failed to clarify the wiki article was referring to terrestrial lava domes, and thus my added comment that gravity variations between Earth and Moon could make a difference in the stability of lunar domes.
Reply | Report Abuse | Link to thisAs for the lava tubes I mentioned, these were actually discovered through NASA (photos on NASA's site) via photographs fly-bys.
Reply | Report Abuse | Link to this"The spacecraft found a number of domelike features with steeply sloping sides—telltale signs of lunar volcanoes."
Reply | Report Abuse | Link to thisAn alternative reason for domes has been seen on Earth for centuries, ie fulgamites. These are the effect of negative lightning striking metallic surfaces. Experiments with hv plasma discharge show dome-like protrusions with one polarity; craters are etched with the other polarity. I've had over 500 hits on my wiki-how webpage demo: wikihow.com/Etch-Your-Own-Crater.
Perhaps in ancient times the moon suffered interplanetary discharge, which gave rise to her pock-marked appearance? That would also explain the silcates, which are by-products of high-energy electric discharge. Hence the glassy reflective coating to make the moon shine!
I'm just wondering if the questions about lava domes on the moon being habitable are grounded in the mistaken assumption that these "lunar volcanic domes" are hollow inside, like the now gone "super Dome".
Reply | Report Abuse | Link to thisCalling something a volcanic "dome" only refers to the "shape".
Instead of having the classic sharp top, a dome volcano has a rounded top, with no discernible peak, but like a classic volcano it is solid, not hollow.
Think of Mount St. Helens.
Vulcanologists often speak of the "dome" growing in the ruins of the old crater.
It is solid rock, or it will be once it completely solidifies.
Venus has many of these, though their much bigger and flatter, and they too are solid rock.