Ancient impact-scars control regional geology worldwide

Abstract Bombardment of the Earth at an early date established initial conditions that have affected all later regional geology. No part of the Earth's crust escaped. Activity at the brittle-ductile boundary has caused large-diameter scars to be sporadically regenerated upward throughout the four-billion years of our planet's history. Although these three-dimensional 'craterform' scars have evolved in many different manners, and many are covered over at any given time, many retain observable two-dimensional map-outlines with circular curvature. These inherited scar-features have been regenerated 'cold' from below and are fundamentally different from 'astroblemes', as presently defined, whose constituent rocks had been directly subjected to the high temperatures and pressures that accompany extra-terrestrial impacts. The varied present-day manifestations of these scars need to be described and categorized as has been done for faults, folds, rocks, and minerals by earlier workers in the earth sciences.