New field of impact research looks to the oceans



Only 13% of the approximately 165 known terrestrial impact structures have been identified as originating in marine environments. Except for one marine impact that was discovered in a deep sea basin (Figure 1, Table 1), most of the marine impacts have been reported from shallow water marginal or epicontinental seas where characteristic craterform structures developed. Unlike continental impacts, an oceanic impact would generate megatsunamis that could potentially devastate coastlines, destroying coral reefs, destabilizing shelf ice and shelf deposits, and causing the backwash of terrestrial matter. The ejection of large quantities of water and salt into the atmosphere might lead to depletion of the ozone shield and acidification of surface regions, and could affect the Earth's albedo and the power of greenhouse forcing.