When and how did dinosaurs go extinct? It's asteroid versus volcano.

Pedro_P

Allosaurus
Dinosaurs are no match for flaming hot rock.
Pixabay
▼ For 165 million years, dinosaursdominated land, sea, and sky. Long-necked Brachiosauruses lumbered along like mobile four-story buildings. Tyrannosaurus rex chased down prey with 50 to 60 teeth as big as  bananas. Mosasaurs stretching 55 feet from snout to tail terrorized  the seas, consuming everything they could catch.
But 66 million years ago, the world’s climate drastically changed. Dinosaurs had thrived in the warm temperatures and mild weather of the Mesozoic era. All of a sudden, the Earth became much  colder and darker. Plants died and food became scarce. All the dinosaurs—except for the ancestors of modern birds—and three quarters of the creatures living on Earth went extinct.
To this day, scientists debate what caused this sudden change. The leading theoriesinvolve an asteroid strike and a giant volcano.
Both theories start with a rare metal called iridium. This element is extremely rare on our planet’s surface, but does exist in Earth’s liquid core and in space rocks like asteroids. In the rock underneath the Earth’s oceans and continents, there’s a thin iridium layer in what geologists call the K-T Boundary, or the point in the geologic record where they see evidence of the dinosaurs’ mass extinction.
Discovering this layer led scientists to speculate that a giant, six-mile-wide meteor hit the Earth around 66 million years ago. The impact had the force of 10 nuclear bombsand would have thrown massive clouds of iridium dust and other debris into the air, blocking out the sunlight for years.
Researchers discovered an enormous crater in the Yucatan Peninsula in Mexico that may have been in just the right spot to cause maximum destruction, as the rocks in this area may have been especially rich in carbon dioxide and sulfur or hydrocarbons, all of which could have been released into the air upon impact and contributed to the rapid shift in the climate. The crater was also around 66 million years old. Scientists found some other strange clues in the ancient layers: shocked quartz, rock that looks like a massive shockwave rearranged its crystals; soot that suggested widespread wildfires; and glass-like spheres that looked like cooled molten rock. (▪ ▪ ▪)

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niya

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