DINOSAURS, EVOLVED?

Asteroid Impact

The most widely accepted theory is the asteroid collision. This theory was proposed by geologist Walter Alvarez, and his father, physicist Luis Alvarez. A crater, known as the Chicxulub crater, located at the tip of Mexico's Yucatán Peninsula was believed to be created by an asteroid about 65 million years ago.

A thin layer of clay, comprising of a high concentration of iridium was discovered at the KT boundary. What was unusual about this discovery was that iridium was typically found in meteorites, asteroids, and in the Earth's core. This impact was so strong that it created a cloud of debris, disturbing the Earth's atmosphere. The amount of dust and ash produced was believed to be so thick it blocked out sunlight for months, lowering the temperature globally. In addition, the impact produced forest fires, tsunamis, seismic activity, and severe storms. With the damage in the environment, many plants were unable to thrive, leaving dinosaurs with no source of food. For the carnivorous dinosaurs, the environment was in such

 

Volcanic Activity

Another theory proposed was volcanism. As the Earth's core is also rich in iridium, it is believed that a large volcanic eruption left a 2.4 kilometre thick layer of magma. The effects are said to be similar to those that occurred in the asteroid collision theory, where the high levels of iridium gravely affected the environment.

 

Other Theory

There have also been debates whether the extinction of dinosaurs were sudden or it occurred gradually. Some scientists believed that the population of dinosaurs slowly declined, even years before the KT mass extinction. However, this theory is argued, with no apparent evidence during the Late Cretaceous record.