Dinosaurs again

1987/08/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Paleontologia
• Arkeologia

The massive extinctions that marked the passage from Cretaceous to Tertiary have been the subject of debate among scientists and numerous theories have emerged about the origin of these stadiums. Some are supporters of what was inside the Earth. Others, however, refer to external factors. The first theories focus on vulcanism and the second on asteroids and dust clouds. These massive destructions have recently been analyzed in India and have found new data in favor of theories of internal origin.

The black basalts covering the Deccan part have long been known to geologists and this study has set the age of these basalts. The first volcanic eruptions took place 66 million years ago, at the cretace-tertiary limit. This volcanic episode spanned 500,000 thousand years and is sufficient to create inadequate living conditions, especially in the form of acid rain. Thus, the massive appearances in this region were due to the largest volcanic disaster in the last 200 million years.

Geophysicists go deeper and explain the cause of vulcanism. It is noted that the two major known epochs of mass destruction were the two in which the Earth's magnetic field was not invested for a long time. The cause of non-investment could be increased speed of movements occurring in the Earth area. This agitation would cause a tempering anomaly in the lower mantle, which would be noted as vulcanism on the surface.