Block diagram problems concerning relative dating
As it turns out, the Moon is truly a whole new world, with rocks and surface features that provide a record of events that occurred during the first billion years of the solar system.
This record is not preserved on Earth because all rocks formed during the first 800 million years of Earth's history were recycled back into the interior.
These terms are still used today, although we know the maria are not seas of water and the terrae are not geologically similar to Earth's continents.
The maria and terrae do, however, represent major provinces of the lunar surface, each with different structures, landforms, compositions, and histories.
In July 1969, a human stood for the first time on the surface of another planet, seeing landscape features that were truly alien and returning with a priceless burden of Moon rocks and other information obtainable in no other way.
The importance of the Moon in studying the principles of geology is that it provides an insight into the basic mechanics of planetary evolution and events that occurred early in the solar system.
Much of the knowledge we have of how planets are born and of the events that transpired during the early part of their histories has been gained from studies of the Moon.
Some maria occur within the walls of large circular basins such as Crisium, Serenitatis, and Imbrium, whereas others such as Oceanus Procellarum occupy much larger, irregular depressions.
We know from lunar rock specimens and surface features that the maria are vast layers of thin basaltic lava, which flowed into depressions and flooded large parts of the lunar surface.
(NASA) The terrae, or highlands, constitute about two-thirds of the near side of the Moon and exhibit a wide range of topographic relief.