Volcanic activity on the moon began about 3 to 3.5 billion years ago. And until now, astronomers believed that they went cold roughly one billion years ago. But NASA scientists have found strong evidence that the moon’s volcanoes cooled gradually rather than stopping abruptly about a billion years ago. The discovery will have major implications on how warm its interior is thought to be. Many spots experienced volcanic activity much later.
Volcanoes on the moon were more recent than previously thought
NASA’s Lunar Reconnaissance Orbiter (LRO) observed dozens of rock deposits that are less than 100 million years old. In fact, some eruptions are as recent as 33 million years ago. Of course, 33 million years is a very long time period, but it’s really “recent” in terms of geologic time scale where you are talking about billions of years.
John Keller of NASA’s Goddard Space Flight Center said that this finding will make geologists rewrite the textbooks about the moon. The relatively recent basaltic lava deposits are scattered across the dark volcanic plains of the moon. They are characterized by a mixture of shallow, rounded and smooth mounds near patches of rough, blocky terrain. The “irregular mare patches” or IMPs are too small to be seen from the Earth. The images were captured by NASA’s LRO spacecraft.
Late-stage volcanoes an important part of the moon’s history
Scientists identified a total of 70 IMPs on the near side of the moon. Their wide distribution and the large number suggest that late-stage volcanoes were an important part of the moon’s geologic history rather than an anomaly. Only few craters are larger than 20 meters, suggesting a young age. Researchers said steep slopes from smooth rock layers to the rough, blocky terrain are in line with the young age estimates.
One such IMP called Ina was imaged by Apollo 15 astronauts, which was found to be quite young. But due to the lack of other similar features at the time, it was considered one-of-a-kind feature formed by “localized volcanic activity.” But the latest evidence of dozens of IMPs indicates that the volcanic activity in relatively recent times was not restricted to a specific area.