This week, a paper published in Nature presents geochemical evidence indicating that this migration did, indeed, take place.

These may still be confirmed as impact structures by the presence of shocked minerals (particularly shocked quartz), shatter cones, geochemical evidence of extraterrestrial material or other methods.

In some cases, geochemical evidence can be found of metasomatic alteration processes.

But the rock analysis provides more direct geochemical evidence of these forces and their role in the long-term history of Mars.

Despite these uncertainties, the geochemical evidence helps by making scientists focus on theories that are consistent with at least one of the likely environmental changes.

It has been proposed that geochemical evidence supports an early-formed reservoir that survived in the Earth's mantle for about 4.5 billion years.

A widely discussed theory, supported by geochemical evidence in sediments worldwide, holds that an asteroid or comet about six miles in diameter struck Earth 65 million years ago.

Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean.

The study combines geochemical evidence both on temperature, cosmic rays influence and as well astrophysical deliberations suggesting a major role in climate variability over different geological time scales.

However, the composition and origin of the magma which differentiates into granite, leaves certain geochemical and mineral evidence as to what the granite's parental rock was.