Ancient fish bones helped archaeologists pinpoint the season when a massive asteroid struck Earth about 66 million years ago.
About 66 million years ago, an asteroid about 10 kilometers in diameter struck Earth, creating the Chicxulub crater off the coast of present-day Mexico. This catastrophe caused the extinction of the non-avian dinosaurs and many other living creatures.
The impact ejected enormous quantities of material into the atmosphere, including molten rock, dust, and sulfur. A thick cloud of dust and debris from the impact spread across the planet, blocking sunlight and causing severe weather disturbances.
This catastrophe resulted in the extinction of approximately three-quarters of all life on Earth, including all non-avian dinosaurs. It is believed that the initial heat shock was followed by a prolonged cooling period, as vast quantities of sulfur and soot reached the upper atmosphere, blocking sunlight for years.
The sudden cooling caused the death of large numbers of plants and phytoplankton, which in turn led to the collapse of the food chain, from herbivores to their predators.
Although scientists have not yet been able to determine the exact year of the asteroid's fall, they have been able to determine the season in which the disaster occurred, according to the scientific journal "Science News".
Researchers studied fish bones from the Tanis site in North Dakota, where sedimentary rocks recorded the immediate aftermath of the impact. Frozen droplets of molten rock were found in the fish's gills, suggesting they were alive when the debris struck.
The fish bones also retained annual growth cycles in the form of broad and narrow lines. The outer layers of all six specimens showed rapid growth that had not yet reached its summer peak. The growth cessation lines were regular, ruling out starvation or dehydration. This suggests that the fish died in the spring, before the start of summer in the Northern Hemisphere.
The timing of the impact may have affected survival rates. In the spring, young animals that overwintered in their burrows would have emerged, making them more vulnerable. In the Southern Hemisphere, where autumn had arrived, organisms were preparing for winter and were perhaps better protected.
This discovery may help explain why certain animal groups became extinct while others survived.
what is your opinion on this news ?do let us know in the comments on tha comment box
if you liked this news article please share on friends & family & don't forget to follow on website & social media
Ally
ReplyDelete