Meteorite, Volcano, Or Perhaps Something Else?

Probably the most popular theory is that a massive meteorite, estimated to be about 6 miles wide, crashed into the Earth with disastrous effect. The impact crater from a meteorite of this magnitude would be about 110 miles in diameter, and the debris from such an immense explosion would have blown up into the atmosphere, dramatically changing the climate and ecology of planet Earth. This in turn forced the mass extinction of over 75% of all living things including plant life, and a total extinction of those huge creatures we call Dinosaurs.



The theory of an asteroid disaster is best supported by a discovery made in the late 1970’s by Dr Luis Alvarez’s, who’s team of scientists discovered a thin white powdery layer in rock samples that date back 65 million years. This thin layer is believed by many to have been formed by the fallout of debris from the meteor explosion. Since its initial discovery, similar samples have been found all around the world to support this theory.

This thin layer of sediment is commonly referred to as the ‘KT boundary’ because it separates the Cretaceous Period from the Tertiary Period, however we will examine this defining statement in more detail later.



Interestingly enough, this rock layer also contains high elements of iridium, a compound more commonly found in asteroids than the Earths crust. This again lends weight to the theory of a meteorite disaster.

The most fascinating point of interest about the KT boundary is that below the thin sedimentary layer of rock there are plenty of fossilised dinosaurs, yet above the layer there are virtually none. This single fact alone categorically indicates that this is in fact the point at which Dinosaurs became globally extinct.

This theory whilst widely supported does not conclusively prove how the Dinosaurs became extinct, only when they became extinct.

Other common theories for dinosaur extinction run along a very similar vein, but substitute the meteorite strike for global scale volcanic eruptions. The fallout of which, causes both the extinction of the Dinosaurs and the sedimentary layer of the KT boundary. However what these theories fail to explain, is why these global climactic changes only affected large reptiles like the Dinosaurs, and not smaller ones such as lizard's crocodiles and turtles, and even less effected were the vast and diverse variation of small mammals which dominate the living planet on Earth today.

Coming back to our definition of the KT boundary. The mainstream experts note this change between the cretaceous period and tertiary period, as being a change from cold blooded creatures to warm blooded creatures, however this viewpoint is a little ambiguous and leading, as will now be explained in more detail.

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