Posted on 11/25/2014 12:08:45 PM PST by Straight Vermonter
NASA’s Lunar Reconnaissance Orbiter (LRO) has provided researchers strong evidence the moon’s volcanic activity slowed gradually instead of stopping abruptly a billion years ago.
Scores of distinctive rock deposits observed by LRO are estimated to be less than 100 million years old. This time period corresponds to Earth’s Cretaceous period, the heyday of dinosaurs. Some areas may be less than 50 million years old. Details of the study are published online in Sunday’s edition of Nature Geoscience.
“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 in Greenbelt, Maryland.
The deposits are scattered across the moon’s dark volcanic plains and are characterized by a mixture of smooth, rounded, shallow mounds next to patches of rough, blocky terrain. Because of this combination of textures, the researchers refer to these unusual areas as irregular mare patches.
The features are too small to be seen from Earth, averaging less than a third of a mile (500 meters) across in their largest dimension. One of the largest, a well-studied area called Ina, was imaged from lunar orbit by Apollo 15 astronauts.
Ina appeared to be a one-of-a-kind feature until researchers from Arizona State University in Tempe and Westfälische Wilhelms-Universität Münster in Germany spotted many similar regions in high-resolution images taken by the two Narrow Angle Cameras that are part of the Lunar Reconnaissance Orbiter Camera, or LROC. The team identified a total of 70 irregular mare patches on the near side of the moon.
The large number of these features and their wide distribution strongly suggest that late-stage volcanic activity was not an anomaly but an important part of the moon's geologic history.
The numbers and sizes of the craters within these areas indicate the deposits are relatively recent. Based on a technique that links such crater measurements to the ages of Apollo and Luna samples, three of the irregular mare patches are thought to be less than 100 million years old, and perhaps less than 50 million years old in the case of Ina. The steep slopes leading down from the smooth rock layers to the rough terrain are consistent with the young age estimates.
In contrast, the volcanic plains surrounding these distinctive regions are attributed to volcanic activity that started about 3 1/2 billion years ago and ended roughly 1 billion years ago. At that point, all volcanic activity on the moon was thought to cease.
Several earlier studies suggested that Ina was quite young and might have formed due to localized volcanic activity. However, in the absence of other similar features, Ina was not considered an indication of widespread volcanism.
The findings have major implications for how warm the moon’s interior is thought to be.
“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 information is hard to reconcile with what currently is thought about the temperature of the interior of the 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.
LRO is managed by Goddard for NASA’s Science Mission Directorate at NASA Headquarters in Washington. LROC, a system of three cameras, was designed and built by Malin Space Science Systems and is operated by Arizona State University.
To access the complete collection of LROC images, visit
http://lroc.sese.asu.edu/
For more information about LRO, visit:
http://www.nasa.gov/lro
How can they tell with erosion and all that over the years?
(j/k)
Will be of interest.
Moon. Not much erosion, compared to Earth anyway. Just whatever space debris hits it plus thermal stress.
= (J/K) or Just Kidding
Hmmm it rings a bell, like the moon
LOL!!
Young Moon Creationism?
So the volcanism of the Moon killed the dinosaurs? :)
I wonder how much energy is added to the Moon’s interior by gravitational / tidal stresses caused by the Earth’s gravity?
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Well, not exactly . . . . . .
“..............We’d be much more certain in our understanding of the sequence of geological events on the Moon and other planets if we had more samples collected from many different units that are widely spaced in time. It is largely for this reason (among others) that sample return is always a high priority on the “wish lists” of missions compiled by planetary scientists. Unfortunately, such missions are very difficult to conduct because you have to get into (and then out of) the large gravity well of a planet, which makes the mission very expensive. Several groups are investigating alternative means of getting this information – less costly concepts that will enable sample return and remote measurement of absolute ages on other planetary surfaces. If these other means are successful, we may yet be able to obtain the critical information needed to better understand the history of the Moon and planets.”
This time period corresponds to Earth’s Cretaceous period, the heyday of dinosaurs. Some areas may be less than 50 million years old.Sounds like a job for impacts.
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Is that young Vulcan Lunarism ?
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