|Credit: Pixabay / RafaelMousob|
Only 182 impacts have been ‘confirmed’ on the earth. This number may be very low for two reasons. First, numerous impact craters are observed on the moon and other inner solar system bodies. Second, terrestrial impacts have been significantly modified by erosion and the emplacement of lava flows and thick sedimentary cover. The large Vredefort and Sudbury impact structures illustrate the extent of this alteration. Based on this evidence, other impact features may be difficult to identify. Other factors hindering the confirmation of past impacts, especially in the Precambrian, include overly stringent requirements for impacts, thick Phanerozoic cover, and the fact that until recent decades few geologists have been looking for impacts. Indirect evidence for other impacts, especially during the Precambrian, include cratonic basins, other circular or arc-shaped features, impact spherule layers, and other subtle geological and geochemical features. Thousands of impacts may have occurred during the Precambrian. It is likely that many Precambrian sedimentary rocks are Flood deposits, such as black shale, quartz arenite, phosphate-rich rocks, or those with diagnostic fossil traces, such as raindrop imprints. This suggests that many Precambrian impacts occurred during the Flood. These may have contributed to the energy needed to start and sustain the Genesis Flood.To read the rest, click on "Precambrian impacts and the Genesis Flood".