The Moon's crust hardens
The Moon's own ocean of magma freezes over, floating a crust of pale rock that still forms its highlands.
- When
- Known to
- ± 30 million years
- Era
- Hadean
Low-density plagioclase crystallises and floats to the top of the lunar magma ocean, producing the anorthosite highlands that make up the Moon's bright regions. Samarium-neodymium and lead-lead dating place completion at roughly 4.43 billion years. The dark maria are far younger lava flows that filled impact basins long afterwards.