Amber in the Cretaceous deep sea deposits reveals large-scale tsunamis.

Large-scale tsunamis destroy coastal areas and rapidly transport huge amounts of plants and other debris over long distances. However, due to their poor preservation potential and the lack of unequivocal identifying features, tsunami deposits are rarely recognized in the geological record except for geologically young Holocene coastal deposits. This study focuses on pelagic settings as potential archives of large-scale paleo-tsunami events. Here we describe extraordinarily rich amber concentrations in Early Cretaceous deep sea deposits (116-114 Ma). The amber is distinctively deformed in a manner comparable to typical soft-sediment deformation structures such as flame structures. As resin exposed to the air hardens quickly in weeks, the flame deformation of the resin suggests that it reached pelagic seafloors without significant subaerial exposure. This new observation of amber as a soft-sediment unveils the whole sedimentary process from erosion to burial, a view neglected by previous sedimentological studies that focused on clastic and carbonate sediments. The most plausible cause for the presence of this enigmatic amber in a deep-sea setting is large-scale tsunamis, which are supported by the mode of occurrence of amber, associated sedimentary structures, and a massive coinstantaneous landslide.