Eltanin asteroid
Coordinates: 57°47′S 90°47′W / 57.783°S 90.783°W
The Eltanin impact was an asteroid impact in the eastern part of the South Pacific Ocean during the late Pliocene 2.51 ± 0.07 million years ago. The location was at the edge of the Bellingshausen Sea 1,500 km (930 mi) southwest of Chile. The asteroid was estimated to be about 1–4 km in diameter and the impact would have left a crater approximately 35 km across.
The impact was first discovered in 1981 as an iridium anomaly in sediment cores collected by the research vessel Eltanin, after which the impact and asteroid are named. Later studies were done by the vessel Polarstern. Sediment at the bottom of the 5 km (3.1 mi) deep ocean in the area had an iridium enrichment, a strong sign of extraterrestrial contamination. Debris from the asteroid is spread over an area of 500 km2 (190 sq mi). Sediments from the Eocene and Paleocene were jumbled and deposited again chaotically. Also mixed in were melted and fragmented meteorite matter. The area near the Freeden Seamounts over 20,000 km2 (7,700 sq mi) has a meteorite material surface density of 10–60 kg/m2. Of this, 87% is melted and 13% only fragmented. This is the region of the Earth's surface with the highest density of meteorite material coverage.
The disturbed sediment had three layers. The bottommost layer SU IV is a chaotic mixture of crumbled sediments in the form of a breccia. Above this is layer SU III consisting of layered sand deposited from turbulently flowing water. Above this is SU II layer with meteorite fragments and graded silt and clay that settled out of still but dirty water.
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