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Giant Reign

Dinosaur Extinction: One Giant Mystery

Many different species in the history of life on this planet have simply ceased to be. Gone But Not Forgotten these strange animals leave evidence of their existence entombed in the sedimentary layers of the crust. As fascinating as these fossilized discoveries are, what is even more fascinating is the mystery of what happened to them.

The history of dinosaur is undoubtedly the most pressing needs of all records from extinction. Giants that reigned over the land of their disappearance is both perplexing and intriguing.

New theories are formulated as new scientific discoveries are made, but even experts in the field can not agree on the facts behind the end of the age of dinosaurs.

Nestled in the past, the only clues remaining point to a number of different theories.

Asteroids or volcanoes?

Approximately 65.5 million years ago an event occurred that caused the mass extinction of about 70% of land animals and plant species in a relatively short period of geological time. It is called the extinction event Cretaceous-Tertiary mass extinction, or KT. A thin band, a geological signature called the KT boundary, identifies this.

Around the world remains dinosaurs (of non-avian variety) have only been discovered below this KT boundary. This points to the conclusion that dinosaurs became extinct from the right before event or because of it.

Luis and Walter Alvarez, along with scientists from the University of California in the late seventies were studying closely the limit KT in Gubbio, Italy when they made an interesting discovery. In a clay layer on the limit point they found 30 times the normal level of a rare element called Iridium. These high levels of iridium, it has been theorized, could have only come from two sources: either asteroids or violent volcanic activity.

Asteroid

Many in the scientific community have postulated this impact event theory. The theory suggests that a large asteroid fell to earth and created a cloud of dust and other aerosols that blocked the sun's rays for up to one year. This reduction in sunlight radically affected plant and animal life causing a change in the atmosphere. At the time of impact a pulse of intense radiation killed many species and the resulting climate change and global firestorms decimated the rest.Dinosaurs, due to size, were the first to succumb.

Volcanic Activity

The Deccan Traps, located in western India, formed in late Cretaceous Period at the same time as the dinosaurs disappeared from the earth. Traps are a product of violent volcanic eruptions. This theory postulates that the volcanic activity far have released large amounts of sulfuric aerosols and ash into the atmosphere again causing a major shift in the Earth's climate. A change that dinosaurs did not were prepared to survive.

Ice age

Another theory is based on the idea of a significant drop in temperature that caused the dinosaurs to die, while allowing warm-blooded mammals, more isolated to survive. In this case, all plants, animals and marine life that could not adapt Fall temperatures became extinct. A number of scientists pair this theory with the asteroid theory, claiming it was the asteroid that caused the freezing deep.

There are many possible explanations and scientific theories about the extinction of the dinosaurs. The new evidence is discovered all the time, which supports a hypothesis or another, however, the truth is we really do not know what ended the reign of these giants of the prehistoric world.

It is a mystery can remain until the moment of our extinction.

About the Author

Discovery Channel's
Dinosaurs blog
is one of the best
dinosaurs
resource available. Covering a wide range of dinosaur topics as they explore their prehistoric existence all the way up to the time of their extinction.

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