An irregular mare patch also known as an IMP, is a smooth, rounded, slightly mounded area, generally about 500 meters wide, occurring in the lunar maria.
If these features are volcanic in origin, it is “‘literally going to make geologists rewrite the textbooks about the moon'”.
According to the current scientific theories, the Moon’s small size means that its mantle should have fully solidified by about 1 billion years ago, which is backed up by seismic data. This would prevent any further geological action by the Moon’s Interior. A recent (in geological terms) eruption would indicate that the Moon has cooled much more slowly than thought, possibly due to heat released from radioactive decay of radioisotopes in the Moon.