RE: Rio Cuarto dates.

So in other words you intend to finess the data until the you get the date you want? The flooding of the Nile was the basis for Egyptian civilization and was easily subject to climactic variatians wiich happen on a decades scale level. The article I referenced stated a longer time cycle as well. Where is the evidence for an impactor at those other periods and what would cause that periodicity?

RE "By the way, Mars does not have a molten core, and thus lacks a magnetic field to
shield its surface from the sun's radiation - thus it is simply impossible to terra form Mars, or to colonize it "

You are incorrect once again. Terraforming Mars is dependent on how much volatiles Mars currently has available to generate an atmosphere. The lack of magnetosphere means any terraformed atmosphere will be temporary without replenishment on the order of millions of years. A few million years is quite a bit of time to work on methods of replenishment. Protection from solar flares is another issue which arises from the lack of a magnetosphere. However, it must be dealt with on the Moon, Mars, or asteroids with or without terraforming, thus it is not a "barrier" to terraforming. Fortunately the effects on Mars are half what they would be on the Moon due to greater distance.

Regards,
Mark