Cretaceous-Paleogene boundary tsunamite on the Adriatic carbonate platform and possible source of a hypothetical Atlantic-to-western-Tethys megatsunami
Published:September 11, 2019
Tvrtko Korbar*, 2019. "Cretaceous-Paleogene boundary tsunamite on the Adriatic carbonate platform and possible source of a hypothetical Atlantic-to-western-Tethys megatsunami", 250 Million Years of Earth History in Central Italy: Celebrating 25 Years of the Geological Observatory of Coldigioco, Christian Koeberl, David M. Bice
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An unusual deposit at the Cretaceous-Paleogene (K-Pg) boundary within the Adriatic carbonate platform shallow-water succession is interpreted as a major tsunamite, and a possible mechanism that links it to the Chicxulub asteroid impact on Yucatan (Mexico) is speculated. Although the K-Pg boundary hiatus is a common feature within the shallow-marine successions of the Adriatic carbonate platform, three exceptional sections were discovered that are characterized by continuous sedimentation and the event beds at the K-Pg boundary. Two sections include ~5-m-thick coarse-grained complex event beds intercalated within more than 100-m-thick successions of predominantly micritic carbonates deposited in the protected low-energy inner-platform setting, relatively proximal to the platform-margin embayments. The third section is characterized by an ~10-cm-thick event bed showing distinct soft-sediment bioturbation, and it is interpreted as a more distal section. It has been reported previously that the Chicxulub impact cratering generated an almost global tsunami, while the seismic waves caused collapses of the North American southeastern margins. It is hypothesized that the collapses could have generated a megatsunami in the Atlantic Ocean that could pass through a deep seaway between the Atlantic and western Tethys Oceans and finally terminate on the Adriatic carbonate platform, located ~10,000 km from the impact site. Considering the fact that there are potential sedimentological indications for such a huge sedimentary event in NW Africa (Morocco), focused research is needed in the region, along with landslide tsunami modeling, for a relevant evaluation of the hypothesis.
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250 Million Years of Earth History in Central Italy: Celebrating 25 Years of the Geological Observatory of Coldigioco
Central Italy has been a cradle of geology for centuries. For more than 100 years, studies at the Umbria and Marche Apennines have led to new ideas and a better understanding of the past, such as the Cretaceous-Paleogene (K-Pg) boundary event, or the events across the Eocene-Oligocene transition from a greenhouse to an icehouse world. The Umbria-Marche Apennines are entirely made of marine sedimentary rocks, representing a continuous record of the geotectonic evolution of an epeiric sea from the Early Triassic to the Pleistocene. The book includes reviews and original research works accomplished with the support of the Geological Observatory of Coldigioco, an independent research and educational center, which was founded in an abandoned medieval hamlet near Apiro in 1992.