Volcanic eruptions and asteroid caused the extinction of dinosaurs – lagranepoca

The asteroid impact on Earth at the end of the Cretaceous volcanic eruptions sped around the globe, especially in the Deccan Plateau in India. Fotolia

Since the 80s, geologists and paleontologists have debated the role played by two great events asteroid impact on Earth in the Yucatan Peninsula (Mexico) and in vulcanismo- mass extinction occurred at the Cretaceous ended 66 million years ago. While some claimed that the eruptions were irrelevant, others declared that the impact was a brief interruption to extinction already announced.

An international team of geologists has found new evidence that the asteroid impact on Earth accelerated the end of the Cretaceous volcanic eruptions around the globe, especially in the Deccan Plateau in India, where currently the largest volcanic formations of the planet are recorded.

The study, is published in Science indicates that the consequences of the impact, along with the rapid volcanism caused the disappearance of most of the terrestrial and marine life, including the dinosaurs.

” The biggest indicator is that the recovery of the animals to extinction began only when the volcanic activity stopped, “says Paul Renne SINC, lead researcher for the study and director of the Berkeley Geochronology Center (USA), who emphasizes that volcanoes greatly influenced emissions of gases that caused the instability of the weather.

Layers of lava flows of the Deccan Traps in India. / Mark Richards (UC Berkeley)

Frequently eruptions

To reach these conclusions, the team of geologists analyzed flows preserved in the Deccan Traps east of Mumbai (India), where there is a vertical accumulation of a kilometer or more in some places lava. When performing measurements volcanic updated before and after the collision, the researchers found that some subsections of this volcanic region were already active before impact.

“The eruptions occurred while the collision,” says Renne. The new dates indicate that the lava flows in this part of India, which at that time were erupting more slowly, they doubled its business in the thousands of years after the fall of the comet. In addition, from that moment the magma volume increased in each event.

Paul Renne examines the reddish soil of lava flows in the Deccan traps (India). / Mark Richards (UC Berkeley)

“Based on the dating of the lava, we ensure that the impact and volcanism occurring 50,000 years before the extinction, making it difficult to distinguish which killed two mechanisms of life on Earth, “he added the expert. The consequences were dramatic. The planet was completely covered by dust and noxious gases, triggering climate change and wiped out many species

The impact abruptly altered the system of volcanic tubes, which produced major changes in the frequency and chemical eruptions. After this change, volcanic eruptions long delayed the recovery of life on Earth about 500,000 years after the boundary between the Cretaceous and Paelógeno, right at the time when land animals and marine creatures disappeared from the fossil record.

“A biodiversity and ocean chemistry cost them half a million years to recover really between the two eras, that is just the period of the accelerated volcanism,” says the scientist.

For researchers the union of the three events (the collision volcanism and mass extinction) is no coincidence. “It is quite possible that the animals disappear only with the eruptions, as had happened only with the asteroid impact without the contribution of volcanoes-but I personally believe that in these cases the extinctions have been less intense,” explains Renne sync.

Original article here