What was the K-T event?
The K-T event is the widely known term for the Cretaceous-Tertiary extinction event. This event marked the end of the Mesozoic geological era and the beginning of the current Cenozoic era about 65 million years ago. The K-T event was the point of mass extinction for all non-avian dinosaurs, as well as a severe diversification of life on Earth- a total of 70% of life on Earth. The most prominent theory of the cause of the K-T event is a bolide impact. A bolide is the name geologists and astronomers use for a large meteor impactor. The Chicxulub crater, fround in the Yucatan Peninsula in Mexico is 110 miles in diameter, which means that the bolide that created the crater was 6 miles in diameter. The bolide size is estimated could have produced an explosion hundreds of millions of times more powerful than any nuclear weapon created on Earth, and this would just be the start. Material would have been shot everywhere, and the dust created would be trapped in the atmosphere for months, blocking sunlight from reaching the surface and ceasing photosynthesis. Global firestorms, volcanism, acid rain and hurricane-like storms are other proposed contenders. The Earth would have been put in a “nuclear winter” for at least a year which would have ultimately killed off more than 70% of all life. Some mammals and smaller life did survive, and eventually took over after the extreme conditions subsided.
Evidence has shown that it was this bolide impact that caused the K-T event. There has also been the discovery of several other craters formed around the same time as the Chicxulub crater, suggesting possible simultaneous impacts. While the most likely catalyst of the K-T event was a bolide impact, it has been increasingly postulated that conditions on Earth pre-impact the impact contributed to the severity of the effect of the influence on life. One such condition is marine regression, or a large drop in the sea level. This could have caused a partial marine extinction as well as a rise in Earth’s temperature. Another possible contributor to the K-T event is an increase volcanic activity. The best evidence of this is the Deccan Traps, one of the largest remnants of volcanic activity on Earth. The Traps were formed at the end of the Cretaceous period by volcanic eruptions spanning the 2 million years prior to the K-T event. The increased volcanic activity would have released gases into the air, causing the global temperature to rise considerably.
