Editing Oceanus Procellarum (section)

==Late lunar volcanism==
Relatively recent (less than 2 bya) volcanic activity had been suspected in the Oceanus Procellarum due to the presence of relatively uneroded features. The 2020 Chang'e-5 sample return mission provided constraints on the age of Oceanus Procellarum, finding it to be 1963 ± 57 million years old – over a billion years younger than any other previously returned lunar sample. Late lunar volcanic activity was considered surprising as the Moon is much smaller than Earth; interior heat necessary for volcanism should have been lost three billion years ago, so volcanic rocks as late as those found in Oceanus Procellarum must require additional heat sources. 

Previous studies suggested that Oceanus Procellarum should have high concentrations of the heat-producing elements such as potassium, thorium, and uranium{{efn|due to the abundance of their radioactive isotopes providing heat from decay}}, but samples returned showed that the concentration of suspected radioactive elements is much lower than necessary to provide prolonged heating.<ref name="change-5-no-radioactive-elements">{{Cite journal |last1=Che |first1=Xiaochao |last2=Nemchin |first2=Alexander |last3=Liu |first3=Dunyi |last4=Long |first4=Tao |last5=Wang |first5=Chen |last6=Norman |first6=Marc D. |last7=Joy |first7=Katherine H. |author7-link=Katherine Joy |last8=Tartese |first8=Romain |last9=Head |first9=James |last10=Jolliff |first10=Bradley |last11=Snape |first11=Joshua F. |display-authors=etal|date=2021-11-12 |title=Age and composition of young basalts on the Moon, measured from samples returned by Chang'e-5 |url=https://www.science.org/doi/10.1126/science.abl7957 |journal=Science |language=en |volume=374 |issue=6569 |pages=887–890 |doi=10.1126/science.abl7957 |pmid=34618547 |bibcode=2021Sci...374..887C |s2cid=238474681 |issn=0036-8075}}</ref>