Imbrian

The Imbrian is a time in the Moon's history. It has two parts: the Early Imbrian and the Late Imbrian. This time helps us learn how the Moon changed, especially after big events like space rocks hitting it. Scientists study this time to find out more about the Moon's surface and what happened there long ago.

Early Imbrian

The Early Imbrian was a time long ago when the Moon changed a lot. It started about 3,850 million years ago and ended about 3,800 million years ago. During this time, a big crash made the huge Mare Imbrium area on the Moon. Other big areas like Mare Crisium, Mare Tranquillitatis, Mare Serenitatis, and Mare Fecunditatis also formed. These places later filled with a kind of rock called basalt.

This time was after the Nectarian period and before the Late Imbrian. It also happened at the end of a time when many things hit the Inner Solar System.

Late Imbrian

In the Lunar geologic timescale, the Late Imbrian epoch happened from 3,800 million years ago to about 3,200 million years ago. During this time, part of the layer below the moon's surface melted. This melted material filled the moon's basins with a type of rock called basalt. Scientists think this melting happened because big impacts made the surface thinner. This let hotter material from deeper down move closer to the surface. Most moon rocks studied on Earth are from this period.