The hypothesis that an asteroid collision may have caused the extinction of the dinosaurs is primarily supported by several key pieces of evidence:
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Chicxulub Crater: The discovery of the Chicxulub crater in the Yucatán Peninsula, Mexico, is one of the strongest pieces of evidence. This crater is about 150 kilometers (93 miles) in diameter and is believed to have been formed around the time of the dinosaur extinction, approximately 66 million years ago.
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Iridium Layer: A global layer of sediment enriched with iridium (a rare element more commonly found in asteroids) has been identified in the geological record at the Cretaceous-Paleogene (K-Pg) boundary. This layer supports the hypothesis of an asteroid impact, as iridium is not abundant in the Earth's crust but is found in higher concentrations in asteroids.
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Shocked Quartz and Microtektites: The presence of shocked quartz (a form of quartz that has been subjected to intense pressure) and microtektites (tiny glass spherules formed by high-energy impacts) in sediments from the K-Pg boundary further supports the impact hypothesis.
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Mass Extinction Timeline: The timing of the apparent mass extinction event corresponds closely with the dating of the impact. The abrupt disappearance of a large number of species at the K-Pg boundary aligns with the evidence of a catastrophic event.
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Climate Change Evidence: Models and studies suggest that the impact would have thrown massive amounts of debris and soot into the atmosphere, leading to a "nuclear winter" effect with drastic climate changes that could have contributed to the extinction of many species, including dinosaurs.
These combined pieces of evidence provide a strong case for the asteroid collision theory as a significant factor in the mass extinction event that wiped out the dinosaurs.
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