Visible only in certain wavelengths, the deposits are not detectable in the crater image (inset). Large impacts on the Moon can form wide craters and turn surface rock liquid.
Geophysicists once assumed that liquid rock would be homogenous when it cooled. Now researchers have found evidence that pre-existing mineralogy can survive impact melt.
Despite the unimaginable energy produced during large impacts on the Moon, those impacts may not wipe the mineralogical slate clean, according to new research led by Brown University geoscientists.
The researchers have discovered a rock body with a distinct mineralogy snaking for 18 miles across the floor of Copernicus crater, a 60-mile-wide hole on the Moon's near side.
The sinuous feature appears to bear the mineralogical signature of rocks that were present before the impact that made the crater.
The deposit is interesting because it is part of a sheet of impact melt, the cooled remains of rocks melted during an impact.
The assumption was that the impact energy would the elemental composition thoroughly during the liquid phase, mixing all the rock types together into an indistinguishable mass.
Identifying any pre-impact mineral variation would be impossible but this distinct feature found at Copernicus suggests that pre-existing mineralogy isn't always blended away by the impact process.
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| Deepak Dhingra |
"The implication is that we don't understand the impact cratering process quite as well as we thought."
The findings are published in online early view in the journal Geophysical Research Letters.
Reference
"Mineral analysis of lunar crater deposit prompts a second look at the impact cratering process": doi/10.1002/grl.50255/abstract
Read more of this article at Phys.org
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