Among these giant reptiles were the most gruesome and horrific killers that every lived. Yet, despite all of their strength and evolutionary longevity, dinosaurs became extinct about 65 million years ago. Read on and see what you think. While carrying out studies in Italy, Dr. Alvarez observed that there was an unusually high level of iridium at the K-T boundary layer.
Iridium is an element which is rare on earth but is common in celestial bodies, such as meteorites.
It was later noted that this increased level of iridium was present at the K-T boundary throughout the globe. Furthermore, stishovite and tektites, mineral substances formed under conditions of high heat and pressure, were also found at the K-T boundary. Walter Alvarez interpreted these findings as indicating a massive meteorite impact 65 million years ago. Another theory proposed to explain the extinction of the dinosaurs is related to volcanism. It is believed that increased volcanism on the Indian sub-continent resulted in the excessive production of carbon dioxide.