He suggests that Frigoris is actually within the Imbrium basin
, because the extrapolated rim of a circle defined by the Apenninus, Caucasus, and Carpatus ranges passes along the northern shore of Mare Frigoris roughly in the same radial position to the basin's rim as Palus Putredinis, just inside the mountains' long arc.
Researchers have long puzzled over the grooves surrounding the crater known as the Imbrium basin
. Some grooves (https://www.theguardian.com/science/2016/jul/20/astronomers-shine-a-light-on-origin-of-man-in-the-moons-right-eye) reportedly spread out radially and others come from the northwest of the crater.
But the Imbrium basin
, where Chang'e-3 landed, contains some of the younger flows -- 3 billion years old or slightly less.
Chang'e-3, an unmanned lunar mission, that touched down on the northern part of the Imbrium basin
on Moon - one of the most prominent of the lava-filled impact basins visible from Earth - has spotted volcanic rocks unlike those returned by Apollo and Luna missions, Daily Mail reported.
The Imbrium basin
, for example, spans roughly 930 kilometers (580 miles), while that of Mare Crisium (Sea of Crises) near the Moon's eastern limb (edge) is 740 km wide.
Apollo 14 landed in the Fra Mauro highlands, touching down on material ejected billions of years ago from the great Imbrium basin
, 400 miles north.
According to the researchers, the 1,160-kilometer-wide Imbrium basin
, along with the main rock in the meteorite, formed when an asteroid struck the moon 3.909 billion years ago.
But the GML extends beyond the Imbrium basin
, and other impact basins lack similarly weak magnetic fields.
The astronauts collected their samples near the moon's huge Imbrium basin
, and the researchers suggest the cordierite bit was "excavated" by the same impact that formed Imbrium.
There is still some uncertainty as to where the Descartes breccia came from, but many scientists believe the source was either the Nectaris impact basin or the much more distant Imbrium basin
And south of the Imbrium Basin
rim are two other named features: #50 is Sinus Aestuum and #92 is Mare Vaporum, both thought to be small impact basins.
Some big features from long ago--for example, Montes Apenninus, the towering mountain chain created during the Imbrium basin
's excavation 3.8 billion years ago--are still clearly visible.