Ordovician Tsunamis: Summary of Hypotheses and Implications for Geoheritage Resources

Ordovician tsunamis have been hypothesized for more than 25 years, but the related knowledge is yet to be systematized. The published sources bearing the pieces of this knowledge were collected in the course of the specialized bibliographical survey, and these pieces of evidence were summarized and interpreted with special attention to the spatiotemporal distribution of Ordovician tsunamis. It is found that the latter were reported from many places of the world (24 localities are established), which represent the Gondwana periphery, some isolated continental blocks, and terranes. Tsunamis were hypothesized for all epochs of the considered period, but the evidence is especially numerous for the Middle Ordovician. The degree of certainty of the interpretations of these tsunamis is chiefly moderate. It appears that only a tiny portion of Ordovician tsunamis is known, but the amount of available information is expected, taking into account the possibility of finding very ancient tsunamis. The outcomes of this study contribute to a better awareness of the world’s geoheritage resources. The established localities representing Ordovician tsunamis can be considered potential geosites, two of which are promising start points for further, field-based research.