Total disappearances
In various parts of the world a special type of quartz (called impact quartz) has been found that only produces the impact of extraterrestrial bodies.
Researchers Bruce Bohor, Peter Modreski and Eugene Foord have discovered the impact quartz clumps at the boundary of the layers that determine cretaceous and tertiary in eight pits (north Pacific, New Zealand, south Spain, Montana of North America, two in Denmark and two in southern Italy).
These discoveries confirm Luis Alvarez's theory. According to this theory, at the end of the Cretaceous a large meteorite or asteroid struck the Earth forming a layer of dust that surrounded the entire planet and hindered the passage of sunlight. This caused the total destruction of animals and plants. According to this discovery, in all cretace-tertiary boundaries with iridium there must be an impact quartz.
The first data in favor of the impact of asteroids was the proportion of conventional iridium found within the cretaceous/tertiary boundaries. The discovery of an impact quartz in areas with high concentrations of iridium has given a new strength to this theory and has helped to overcome the theory of vulcanism. According to the theory of vulcanism, the disappearance of animals was a consequence of a terrible volcanic activity. The dust thrown by the volcanoes blocked, according to this theory, the light coming from the Sun.
At this time scientists are looking for traces of iridium and quartz impact on the boundaries of other geological epochs. They want to show that the impacts and disappearances are periodic.
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