New NASA research from the Lunar Reconnaissance Orbiter (LRO) suggests the moon's volcanic activity slowed down gradually instead of coming to an abrupt stop about a billion years ago.
LRO looked at rock deposits that were believed to be about 100 million years old, which is about the same time period as Earth's Cretaceous period.
"This finding is the kind of science that is literally going to make geologists rewrite the textbooks about the moon," said John Keller, LRO project scientist at NASA's Goddard Space Flight Center
Deposits scattered across the moon's volcanic plains were characterized by smooth shallow mounds and rough terrain; there were about 70 of these irregular patches across the near side of the moon, which is more than researchers previously predicted.
The number of these features, dubbed irregular mare patches, suggest volcanic activity was a significant part of the moon's history. Three of these patches are believed to be less than 100 million years old and even as young as 50 million years. The volcanic plains surrounding these regions have been attributed to volcanic activity that took place as far back as three-and-a-half billion years ago and ended about one billion years ago. At this point volcanic activity is believed to have subsided.
"The existence and age of the irregular mare patches tell us that the lunar mantle had to remain hot enough to provide magma for the small-volume eruptions that created these unusual young features," said Sarah Braden, a recent Arizona State University graduate and the lead author of the study.
The new findings could help researchers gain insight into the temperature of the interior moon.
"These young volcanic features are prime targets for future exploration, both robotic and human," said Mark Robinson, LROC principal investigator at Arizona State University.
The findings were published Oct. 12 in the journal Nature Geoscience.
