Environmental impact of ImpactsTsunami from the Chicxulub impact deposited material widely and often far inland; recognition of such deposits in Haiti, Texas and Florida helped to confirm the nature and location of the event. The tsunami generated by the Eltanin impact about 2 million years ago is shown on the two maps on this page.
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PDF versionTwo Catastrophe ScenariosAbout 2.2 million years ago, a chunk of space debris about a kilometer in diameter splashed down in the Bellingshausen Sea between Antarctica and South America. It was some splash! The splash zone was about 20 kilometers across, waves 4 kilometers high raced away from Ground Zero, and a column of salt water ascended miles high into the upper atmosphere. The TNT equivalent is estimated at 12 billion tons. Ice clouds formed and shaded the planet, causing severe climate changes. On the floor of the Bellingshausen Sea, 5 kilometers deep, lies the Eltanin Impact Structure.
by William CorlissOcean splashdownAn asteroid between one and four km in diameter that splashed into the Southern Ocean, 1500 km SW of Chile, just over two million years ago, may have worsened a period of global cooling that saw the emergence of modern humans... The impact in question was first discovered during a cruise of the Eltanin in the 1960s: betrayed by anomalously high amounts of iridium in ocean-bed cores... Gersonde and his colleagues have taken another look, their results coming from a cruise in 1995 by the research ship Polarstern. The impact left a distinctive 'signature' of geological layers, very like that of the Chicxulub impact. Lowest in the 'impact' sequence is a thick layer of disordered rubble, full of chunks of rock up to 50 cm across: this layer represents the large-scale disturbance immediately after the impact as the ten-megaton blast ripped up the ocean floor. This layer took around four hours to settle after the blast. Smaller particles, such as grains of sand, took longer to settle, explaining why this layer was found immediately above the rubble layer. Capping the whole sequence is a thin layer of very fine sediment, dispersed over a wide area. This would have contained fine-grained material (including vaporized asteroid) flung high into the air and which took days or months to settle out. This layer contained the iridium.
by Henry Gee
UC Davis Geology Department
Eltanin impact
I've seen energy calculations done in about 1968 that claimed such an event would create an enormous amount of heat-energy to "pastuerize most of the planet". Part of the hypothesis concernered studies of Verdevoort Ring in S. Africa & other large scale ancient impact sites, and concluded an object of this size would be sufficient, in a water strike, to crack the mantle, and release enormous amounts of magma, which would create a relatively long term additional vaporization. In turn, the vaporization would slow heat disipation and radiation to space. In effect, there would be an essentially dry area of ocean floor, with a wall of seawater surrounding it, and a rising column of superheated steam for a fair amount of time, until the seawater managed to cool the crater enough to reinundate it.
The results indicated a significant rise in atmospheric temperature, torrential rains & winds, followed later by 'atomic winter' type cooling. It was a scenario of a major global killing event regardless of impact point, assuming a strike in 1-3 Km depth ocean.
In addition, naturally, they mentioned the super-tsunamis this would also create.
Before anyone goes off on me, the third one here isn't directly related -- just pertinent because A) impact is involved, albeit a different one, and B) Antarctica is involved.Iridium-rich layers and catastrophismKyte et al have discovered a 2.3-million year-old sedimentary layer under the Antarctic Ocean that contains iridium and gold concentrations comparable to those in the Cretaceous-Tertiary boundary. The noble metals are mostly contained in millimeter-sized grains that resemble ablation debris from a large extraterrestrial object. Unlike the Cretaceous-Tertiary episode, however, the newly found layer is not accompanied by evidence of mass biological extinctions.
William R. Corliss
Science Frontiers
No. 18: Nov-Dec 1981When Antarctica Was GreenPeter Webb and his coworkers have found pollen and the remains of roots and stems of plants in an area stretching some 1300 kilometers along the Transantarctic Mountains. The Antarctic wood is so recent that it floats and burns with ease. Webb's group postulates that a shrub-like forest grew in Antarctica as recently as 3 million years ago... Nevertheless, these deposits of fresh-looking wood do suggest that trees recently grew only 400 miles from the South Pole. Also of interest is the fact that the sedimentary layers containing the wood have been displaced as much as 3000 meters by faults, indicating recent large-scale geological changes.
William R. Corliss
Science Frontiers
No. 45: May-Jun 1986An Antarctic Bone BedW. Zinsmeister was accustomed to scoff at the idea that the Age of Dinosaurs ended violently with the impact of a giant asteroid some 65 million years ago. He always asked: "Where's the layer of burnt and twisted dinosaur bones?" His certainty was shaken, however, when he began mapping fossil deposits on Seymour Island, Antarctica. He didn't find the dinosaur bones but rather a giant bed of fish bones at least 50 square kilometers in area. Some sort of catastrophe must have annihilated untold millions of fish. And guess what? This great bone bed was deposited directly on top of that layer of extraterrestrial iridium that marks the 65-million-year-old Cretaceous Tertiary boundary at many sites around the world.
William R. Corliss
Science Frontiers
No. 104: Mar-Apr 1996
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