|Sedimentology of tsunamiites reflecting chaotic events in the geological records - significance and problems|
Shiki, T.; Tachibana, T. (2008). Sedimentology of tsunamiites reflecting chaotic events in the geological records - significance and problems, in: Shiki, T. et al. (Ed.) Tsunamiites: features and implications. pp. 341-357
In: Shiki, T. et al. (Ed.) (2008). Tsunamiites: features and implications. Elsevier: Amsterdam. ISBN 978-0-444-51552-0. xiii, 411 pp., more
Geological record; Sedimentology; Tsunamis; Marine
Tsunamis, Tsunamiites, Sedimentology, Chaotic events, Geohistory, Gaia
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Ancient tsunamiites potentially present information about cosmic, global and regional events and processes, including the dynamics of the galaxy, the solar system, the earth and regions on earth. Investigation of impact tsunamiites is particularly significant for global studies of the earth’s past; therefore, the present contribution is focused on this specific type, while ancient volcanism and slide-induced tsunamiites are not dealt with in detail. The occurrence of tsunamiites reflects the occurrence patterns in time of tsunamis, including the frequency of impact-induced tsunamis and the recurrence rate of earthquake-induced tsunamis. This may help to find out records of ancient tsunamis. For example, a high frequency of impact tsunamiites between 1.5 and 1.9 Ga is expected because of the meteorite-impact periodicity that has been proposed on the basis of impact craters. Earthquake-induced tsunamis reflect global and regional tectonics such as plume tectonics, plate-subduction tectonics and ridge subduction, and tend to occur with higher frequencies during sea-level rise than during sea-level fall. As far as studies of the pre-Quaternary are concerned, submarine tsunamiites are more important than the run-up tsunamiites on land, because of their preservation potential. It is suggested that the possibility is relatively high to find tsunamiites in bays and shallow seas. Tsunami-induced sediment gravity-flow deposits as those of the Mediterranean homogenite-type deposits may be found much more often in prehistorical and older sedimentary records than has previously been expected.