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Credit – Scotese Paleomap project (this map shows the position of continents when the cretaceous Paleogene mass extinction occurred )
Do you know what happened on the very day dinosaurs died?
Well, according to the latest research done by geologists, it was the spring season in the Northern Hemisphere ( Autumn in the southern hemisphere) when the dino-killing asteroid smashed into the Yucatán Peninsula, off the coast of Mexico (present-day Chixulub).
In a paper recently published in nature, scientists used fossils from a site in North America in North Dakota’s southwest region known as Tanis.
The fossils were deposited by a seiche in a river. seiche is similar to a tsunami wave, but it happens inland, perhaps due to a strong earthquake.
The fossils of the fish present here contained glass spherules that were created due to the asteroid impact, which threw a large amount of molten rock material into space. The liquid rock crystallized, & cooled in space, and fell back down all over the planet. The fish that lived here ingested these and got trapped inside them.
Further researchers were able to figure out the season using the bones of fish.
The timing of the impact was also crucial from our point of view because, during spring, mammals hibernate underground and were very lucky when the asteroid struck
The asteroid that struck the Yucatán Peninsula 66 million years ago, was at least the size of Mount Everest. It managed to wipe out more than 70 % of all life present on Earth during that time, including the non-avian dinosaurs & giant reptiles.
This event is officially known as the "Cretaceous Paleogene (K- Pg) mass extinction".
The initial impact itself released energy equivalent to billions of nuclear weapons all at once. Thermal radiation melted & vaporized anything within a radius of 1500 km, & the impact debris caused the atmosphere to heat up.
The remainder of the energy was transferred into the Earth's crust, resulting in magnitude 11 earthquakes and volcanic eruptions.
Massive wildfires raged for months across the globe, releasing aerosols and soot into the upper atmosphere, causing temperatures to plummet and the planet to enter a period of darkness comparable to a nuclear winter. Global photosynthesis was halted due to a lack of sunlight, but fungi thrived on the corpses left behind.
Some debates are still raging on this issue, as the Deccan Traps of India were erupting before the Asteroid struck, either way, it seems that the Global ecosystem was already collapsing 66 million years ago.
You can learn more about this topic on -
Palaeocast | Palaeontology podcasts
BBC One and David Attenborough to reveal the final day of the dinosaurs - Media Centre
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