Brown University | 2017 Mar 28
[img3="Ina: New research looks at how this strange volcanic caldera on the Moon was formed. (Credit: NASA/GSFC/ASU)"]https://news.brown.edu/files/styles/hor ... lique2.jpg[/img3][hr][/hr]A young-looking volcanic caldera on the Moon has been interpreted by some as evidence of relatively recent lunar volcanic activity, but new research suggests it's not so young after all.
While orbiting the Moon in 1971, the crew of Apollo 15 photographed a strange geological feature -- a bumpy, D-shaped depression about two miles long and a mile wide -- that has fascinated planetary scientists ever since. Some have suggested that the feature, known as Ina, is evidence of a volcanic eruption Moon within the past 100 million years -- a billion years or so after most volcanic activity on the Moon is thought to have ceased.
But new research led by Brown University geologists suggests that Ina is not so young after all. The analysis, published in the journal Geology, concludes that the feature was actually formed by an eruption around 3.5 billion years ago, around the same age as the dark volcanic deposits we see on the Moon’s nearside. It’s the peculiar type of lava that erupted from Ina that helps hide its age, the researchers say. ...
Ina Pit Crater on the Moon: Extrusion of Waning-Stage Lava Lake
Magmatic Foam Results in Extremely Young Crater Retention Ages - Le Qiao et al
- Geology (online 15 Mar 2017) DOI: 10.1130/G38594.1
