Background
Let us consider the possibility that both the dark spots on the Moon (mare) and the continental flood basalts on Earth could have been caused by the same event. 
We know when Earth’s greatest flood basalts were formed (at the P-T Boundary 250 million years ago) because we have Earth’s geologic table readily accessible. Is it possible that the mare were formed around the same time by the same forces? There are similarities between lunar flood basalts and the Earth flood basalts that have long intrigued lunar observers. With this premise in mind, dating of the lunar mare becomes very important.
- Dating the Lunar Mare
- Scientific Inquiry Alters its Course
- The Model of Intense Bombardment
- Mysteries Solved
Dating of the Lunar Mare
Prior to the Apollo mission scientists were limited to visual inspection of the Moon from Earth. The cratering dichotomy between the lunar mare and lunar highlands was particularly revealing. The highlands are cratered so intensely that it is difficult to identify one crater from another whereas the lunar mare is very sparsely cratered. Scientists counted the craters on the newly formed mare and used their best approximation of the current cratering flux, the rate of meteorite impact, to obtain ages for these secondary lunar surfaces. Pre-Apollo crater dating of the lunar mare using this method set the age at less than 1 billion years old and possibly as young as 700 million years. (2) Since the mare had far fewer craters than the highlands, it made sense that it was much younger.
Scientific Inquiry Alters its Course
Once the Apollo mission brought back rocks from the Moon, isotopic dating drastically revised the age of the mare to more than 3 billion years. This re-dating of the mare after Apollo caused an abrupt change in the direction of scientific inquiry. Rather than resolving lunar origin mysteries, as expected, this paradigm shift instead created new contradictions and deepened existing questions, especially as we learn more about cratering on Mars and other planetary bodies in the solar system.
But what if the isotopic dating is wrong? It is important to point out that there was no real debate over the lunar mare dating. The isotopic dating was accepted carte blanche. It is at this exact point that lunar science lost the scent of the hunt. The scientific literature clearly shows that the hunt for the answers to the origin of the Moon was to only become more confused as time proceeded. Ultimately the greatest scientific disappointment of the Apollo program was its failure to answer the question of lunar origin.
Did you know?
Two rather important papers by two important scientists (3,4) were published just as the new isotopic dates from Apollo were being released and contain apologies as footnotes because they were still using young 1 b.y. crater dating ages of the lunar mare.
The Model of Intense Bombardment (MIB)
All current lunar origin models, including the most widely accepted collision model, do not attempt to answer the lunar mare dating question and generally accept the isotopic dating. What the isotopic dating did not do was change the reality of the low number of craters found on the mare. The model of intense bombardment was constructed in an attempt to reconcile the low crater count findings, once thought to indicate a young mare, with an ancient formation of the mare as now proposed by the isotopic dating. The MIB did this by assuming an early and intense bombardment of the Moon’s highlands during a brief period prior to mare formation, followed by very low cratering as seen on the mare since then.
- Ancient placement of mare formation
- Crowds pre-mare cratering into first tenth of lunar history
- Based on isotopic dating of Apollo mare rock
If we apply the MIB to the Moon then of course we must also apply it to the entire solar system. However, recent findings on Mars make it more difficult to support the MIB and bring the isotopic dating into question.
Mysteries Solved
The historical lunar orbit suggests that the Moon approached the Earth at sometime less than 1.3 to 1.8 billion years ago. If the Moon and Earth got close enough to each other, the close gravitational interaction of these two massive planetary bodies would have caused tidal heating in the same time frame on both the Earth and Moon, resulting in the simultaneous formation of the lunar mare and Earth’s continental flood basalts.
Mysteries in the Earth-Moon System
- The Moon does not orbit around the Earth’s spin axis as would be expected.
- The Moon is retreating from the Earth
- The Moon is tidally locked to the Earth, ie. Always shows the same face.
- The Earth has an unstable rotation full of wobbles and processions.
- The Earth is tilted 22 1/2 degrees.
If we are willing to consider the possibility that the isotopic dating is not accurate and consider a more recent formation of the mare, things start to fall into place and anomalies in the Earth-Moon system begin to be understood. Earth’s unexplained wobble and axial motion, the Moon’s tidal lock and retreat from the Earth, modern plate tectonics, Earth’s continental flood basalts, and the Permian Extinction all can be explained by a gravitational interaction between the Earth and Moon.