Title: On a Possible Giant Impact Origin for the Colorado Plateau,
Abstract: It is proposed and substantiated that an extraterrestrial object of the
approximate size and mass of Planet Mars, impacting the Earth in an oblique
angle along an approximately NE-SW route (with respect to the current
orientation of the North America continent) around 750 million years ago (750
Ma), is likely to be the direct cause of a chain of events which led to the
rifting of the Rodinia supercontinent and the severing of the foundation of the
Colorado Plateau from its surrounding craton.
It is further argued that the impactor most likely originated as a rouge
exoplanet produced during one of the past crossings of our Solar System through
the Galactic spiral arms in its orbital motion around the center of the Milky
Way Galaxy. Recent work has shown that the sites of galactic spiral arms are
locations of density-wave collisionless shocks. The perturbations from such
shock are known lead to the formation of massive stars, which evolve quickly
and die as supernovae. The blastwaves from supernova explosions, in addition to
the collisionless shocks at the spiral arms, can perturb the orbits of the
streaming disk matter, occasionally producing rogue exoplanets that can reach
the inner confines of our Solar System. The similarity between the period of
spiral-arm crossings of our Solar System to the period of major extinction
events in the Phanerozoic Eon of the Earth's history, as well as to the period
of the supercontinent cycle (the so-called Wilson Cycle), indicates that the
global environment of the Milky Way Galaxy may have played a major role in
initiating Earth's past tectonic activities.