Eltanin impact

The Eltanin Impact

The Eltanin impact is a hypothesized extraterrestrial impact event that is believed to have occurred in the eastern South Pacific Ocean approximately 2.51 million years ago, near the boundary of the Pliocene and Pleistocene epochs. Evidence for this event comes from scientific investigations of sediment cores collected by the research vessel Eltanin, after which the impact and its suspected bolide are named. The impact site is located in the north of the Bellingshausen Sea, about 1,500 kilometers southwest of Chile, where the ocean floor is between 4 and 5 kilometers deep.

Description and Evidence

No physical crater has been discovered to date, suggesting the impact likely occurred in deep ocean water. The primary evidence supporting the Eltanin impact is a significant anomaly of iridium, an element rare on Earth's surface but common in asteroids, found within sediment cores. Further studies, including those by the vessel Polarstern, revealed chaotic layers of jumbled and redeposited sediments, mixed with melted and fragmented meteorite material. The area near the Freeden Seamounts exhibits a high density of meteorite material, with a significant portion being melted. The disturbed sediment layers, described as a breccia (SU IV), overlaid by sand deposits from turbulently flowing water (SU III), and finally meteorite fragments settling from quiescent water (SU II), all point to a catastrophic event.

The Impactor and Potential Consequences

The celestial body responsible, known as the Eltanin asteroid, is estimated to have been between 1 and 4 kilometers in diameter and traveling at high speed. The size was inferred from the amount of iridium found. Remnants suggest the asteroid's composition was similar to low-metal mesosiderites. The impact itself is theorized to have evaporated approximately 150 cubic kilometers of water, generating colossal tsunami waves potentially hundreds of meters high. Erosional features and chaotic deposits found on Pacific Ocean shorelines, including large boulders mixed with marine fossils, support the occurrence of such megatsunamis. Waves of significant height are calculated to have reached coastlines as far away as Chile, the Antarctic Peninsula, Tasmania, Fiji, Central America, and New Zealand.

Possible Role in Ice Age Initiation

There is speculation that the Eltanin impact may have played a role in triggering the onset of the ice age in the Northern Hemisphere. At the time of the impact, Earth was undergoing a cooling trend. The hypothesized disruption to the atmosphere, including the injection of water and salt, potential damage to ice shelves and the ozone layer, and increased Earth's albedo, could have contributed to the initiation of glaciation.