posted on 25 March 2016
from the Daily Reckoning, Daily Reckoning
-- this post authored by Stephen Petranek
One of the greatest remaining mysteries about life on Earth and its geology is exactly what happened 65½ million years ago when one of the three largest asteroids ever to strike the home planet landed near what is now the Yucatan Peninsula of Mexico and blew out a hole 190 miles across and more than 12 miles deep.
The impact created what is now the Caribbean Sea, along with a nuclear winter of dust that blanketed out the sun for up to a decade, killing plant life around the Earth and destroying the food sources for dinosaurs.
We have suspected this for only 40 years, after two oil geologists working for the Mexican oil giant Pemex discovered a remarkably symmetrical underwater ring in the Caribbean in the late 1970s.
A few years later, a student and his adviser at the University of Arizona published a paper theorizing that the great Cretaceous-Paleogene extinction event of 65 million years ago must have been caused by an asteroid impact. They went looking for a crater to match the event. It wasn't until satellite imagery was available in the 1990s that they found one - in the Caribbean. Now many scientists are convinced that an asteroid took out the dinosaurs - as well as three-fourths of all plant and animal life.
This month, a $10 million project funded by the European Consortium for Ocean Research Drilling and the International Continental Scientific Drilling Program will establish a platform about 20 miles offshore of the Yucatan Peninsula and begin drilling into what is described as the peak ring of the impact - the largest of several raised rings that formed near the center of the crater when material blasted out of the hole by the asteroid resettled back into it.
The Caribbean Sea probably was formed by an asteroid six miles across that struck near the Yucatan peninsula 65.5 million years ago. The subsequent sulfur thrown into the atmosphere and other debris created acid rain that killed flora and blocked the sun for so long that most of the plants and animals on Earth went extinct.
Scientists believe that when an asteroid impact occurs, the forces are so great, including heat, that the Earth's rock crust melts and becomes more like a liquid, forming waves, or rings, as material pushed out of the hole by the asteroid returns.
The drillers will try to get 1,500 meters deep into the ring, almost a mile down. Some researchers believe unusual life-forms may have established themselves in the hot rings after the impact. The core samples may be able to shed light on how long it took life to recover after the impact as well as traces of life that have evolved since.
Because the crater's identity is so new and has only recently been measured in any significant way, it remains an unexplored key to the past for scientific research and is certain to reveal a number of surprises as the cores from the drilling are examined in years to come.
To your health and wealth,
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