Eltanin impact
Eltanin impact | |
---|---|
Impact crater/structure | |
Confidence | Hypothetical |
Diameter | 35 km (22 mi) |
Impactor diameter | 1–4 km (0.62–2.49 mi) |
Age | 2.51 ± 0.07 Ma, earliest Pleistocene |
Location | |
Coordinates | 57°47′S 90°47′W / 57.783°S 90.783°W |
The Eltanin impact is thought to be an
Description
The possible impact site was first discovered in 1981 as an
The disturbed sediment had three layers. The lowermost 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, consistent with having been deposited from turbulently flowing water. Above this is SU II layer with meteorite fragments and graded silt and clay that plausibly settled out of still but dirty water.[7]
Asteroid
The supposed impacting body, the Eltanin asteroid, is estimated to have been between one and four km (0.6 and 2.5 mi) in diameter and traveling with a speed of 20 km/s (45,000 mph). The possible size of the asteroid was calculated by the amount of iridium found in the disturbed sediments. Assuming that there were 187
The composition of suspected asteroid remnants has been classified as low metal
Tsunami
On the shorelines of the Pacific Ocean there are erosional features that are indicative of a very large tsunami. These include an erosional surface and chaotic deposits of mixed terrestrial and ocean-derived sediment. Boulders as big as buses are mixed with marine fossils and mud. The most well-characterised tsunami deposits are near the coast of Chile. Off the coast of Antarctica there are mudslides into the deep ocean from this age.[10]
The size of a possible tsunami has been calculated. An asteroid that was four km (two mi) in diameter falling onto the five km (three mi) deep ocean would have blasted the water off the ocean floor for at least 60 km (37 mi), and made a wave over 200 m (660 ft) high on the southern end of Chile and the Antarctic Peninsula. After ten hours, waves around 35 m (115 ft) would reach Tasmania, Fiji and Central America, and the New Zealand east coast would have been washed with 60 m (200 ft) high waves. If the impact object was one km (0.6 mi) in diameter, the wave heights would have been one-fifth as great.[3]
Ice age trigger
At the time of the impact in the
See also
- Karakul crater – a large impact crater which may be just a few million years older than Eltanin
- List of possible impact structures on Earth
- Megatsunami of Ranquil Formation – Miocene and Pliocene sedimentary formation in south-central Chile
References
- S2CID 131415717.
- ^ a b c Gersonde, R.; F. T. Kyte; T. Frederichs; U. Bleil; H. W. Schenke; G. Kuhn (2005). "The late Pliocene impact of the Eltanin asteroid into the Southern Ocean – Documentation and environmental consequences" (PDF). Geophysical Research Abstracts. European Geosciences Union. Retrieved 8 October 2012.
- ^ doi:10.1016/s0967-0645(01)00147-3. Archived from the original(PDF) on 5 May 2014. Retrieved 8 October 2012.
- S2CID 140649899.
- S2CID 4362591.
- S2CID 4332536.
- ^ a b Kyte, Frank T.; Rainer Gersonde; Gerhard Kuhn (2005). "SEDIMENTATION PATTERNS OF METEORITIC EJECTA IN ELTANIN IMPACT DEPOSITS AT SITE PS58/281" (PDF). Lunar Science and Planetary Conference XXXVII. Houston Texas. Retrieved 8 October 2012.
- ^ Gersonde, Rainer; Frank T. Kyte; T. Frederichs; U. Bleil; Gerhard Kuhn (2003). "New Data on the Late Pliocene Eltanin Impact into the Deep Southern Ocean" (PDF). Large Meteorite Impacts. Retrieved 8 October 2012.
- ^ Kyte, Frank T.; Chikako Omura; Christopher Snead; Kevin D. McKeegan; Rainer Gersonde (2010). "Trace Elements in Refactory Eltanin Impact Spherules" (PDF). 41st Lunar and Planetary Science Conference. Retrieved 8 October 2012.
- ^ Gary, Stuart; James Goff (26 September 2012). "Earth's ice age asteroid". Starstuff. ABC radio. Retrieved 8 October 2012.
- ^ University of New South Wales (19 September 2012). "Did a Pacific Ocean meteor trigger the Ice Age?". Retrieved 8 October 2012.
- ^ Gersonde, Reiner (2 March 2000). "Oceanic Impacts and Related Environmental Perturbations" (PDF). Catastrophic Events Conference. Retrieved 8 October 2012.
External links
- Rainer Gersonde (2003). "Reports of discovery of the "Eltanin Crater" are contradicted by data" (PDF). Large Meteorite Impacts.
- Peng, H. (February 9–12, 1994). "An Extraterrestrial Event at the Tertiary-Quaternary Boundary". Abstracts of Papers Presented to "New Developments Regarding the KT Event and Other Catastrophes in Earth History. 825. Houston, Texas: 88. Bibcode:1994LPICo.825...88P.