At the end of 1970, Walter and Luis Alvarez discovered a high level of iridium inexplicable to the KT boundary in Gubbio, Italy. The amount of iridium, at this point was 30 times higher than that of other layers of rock above and below the border. Alvarez's team argues that approximately 65 Ma, the earth a celestial body, probably a meteorite, was responsible for the high level of iridium affected.
A theory has been advanced that would be the limitformed by sediment accumulating 30 times slower than normal. But since the discovery by the Alvarez team, the more discoveries in other parts of the world, the KT boundary shows that all concentrations of iridium standard 30 times the excluded, the theory of slow sedimentation.
Massive celestial objects traveling at high speed would be high kinetic energy, and when the earth, they did quickly, the rate of conversion of energy would be enormous. The effectswould be excavated, and subject to intense heat to melt rock and lava as a spray into the atmosphere. Tsunamis would occur at the point of impact points real or, if more than one piece of meteorites on Earth from that moment on what has been proposed.
Evidence supporting the impact theory includes the following:
1. The excess of iridium in my old 65 soil layer has been confirmed in many places in the world.
2. The layer of medium containing the samequartz grains, which were deformed by high pressure shock as he came in a huge explosion. (The deformation is a microscopic structure called twinning in crystals).
3. There are occasional diamonds minutes in extreme conditions, high pressures format.
4. Glass beads were cooled droplets of melted rock ejected into the format.
5. The layer of soil that contains carbon black sufficient to meet all the burning of forests worldwide. This suggestsground fires that have been touched by the impact.
6. The layer of soil itself, particularly around the Gulf of Mexico, contains large deposits of rock falls, would be produced in a large tsunami, or tidal wave. "The geographic distribution of tsunami deposits suggest the effect was in the Caribbean .
7. After a decade of research, scientists have identified in 1990, the crater associated with this material. It is no longer visible on the surface of the earth, butburied under sediment. It covers the coast of Yucatan in the Mexican province of Chicxulub. It 'was the picture of the strength of the gravitational field on the surface, and through the holes showed that dated to 65 mA old. E 'was identified as an impact crater.
8. Astronomers have mapped many asteroids cross Earth's orbit. Statistics from studies of the orbit is estimated that a 10 km size asteroid could hit Earth about every 100 or so my - that fits with the idea thatWe actually hit 65 my ago to receive an object of this size. (Small strokes are much more common).
9. For the KT boundary in the world, there is a wide diversity of fossil plankton in the limit (over the age of 65 mA), but very few fossils in the layer, providing further evidence for mass extinction at the time.
Another cause of the KT boundary and mass extinction has been proposed to examine the impact theory. Of flood basalts. Detailed radiometricTests have shown that large magma occurred on both sides of the KT boundary. It 'was the result of India are pushing for a hot spot during the continental drift. was the large amount of pyroclastic materials and gases emitted by the full basalts significant extinction of numerous species of life caused. Sulfur dioxide leads to acid rain, the pH of ocean water would decline. Carbon dioxide, which would have been issued in this case global warming.The dust released by the activity would increase the albedo of the earth and cause cooling. sulfur dioxide, carbon dioxide and dust affects climate and spread rapidly around the Earth, a prerequisite for the mass death. Foraminifera with calcareous shells would not survive in the acidic conditions of the sea. The powder would have prevented the photosynthesis of phytoplankton, which die and no longer part of the food chain for a longer lifeForms, which also die.
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