What killed off the dinosaurs

Question

Do you really think it was an asteroid ?

Answer 1

nope...it was chuck norris

Answer 2

Almost all paleontologists are sure of it.

Iridium is a rare metal on the earth, but common in asteroids.  Where ever in the world you look for dinosaur fossils you find a thin layer of iridium on top of them, and always at the same geological time period.  After that line of iridium you find zero signs of dinosaurs; this points to a mass extinction.  The asteroid collision is a normal conclusion because where else could the iridium have come from AND have been spread across the earth in a thin layer?

The exact reason for the massive die off of dinosaurs will remain unknown until someone actually goes back in time to the event; but we can make some pretty good deductions based on fossilized evidence.  I have heard one theory proposed that the dinosaurs could have been on the edge of the extinction due to a plague or excessive volcanic activity and the asteroid collision could have pushed them over the edge.  However, how would the plague spread across all the continents when they were separated by the oceans and it would take a lot of volcanos blowing at the same time to create a big enough problem to kill off so many species?  Neither theory explains the layer of iridium and why it is always on top of the last dinosaur bones found. Granted the ocean gap wasn’t as large as it is now days, but Pangea had broken up before the Cretaceous the last time we find dinosaurs.

According to Wikipedia:  http://en.wikipedia.org/wiki/Kt_event

“The Cretaceous–Tertiary extinction event was a large-scale mass extinction of animal and plant species in a geologically short period of time, approximately 65.5 million years ago (Ma). It is widely known as the K–T extinction event and is associated with a geological signature, usually a thin band dated to that time and found in various parts of the world, known as the K–T boundary. K is the traditional abbreviation for the Cretaceous Period derived from the German name Kreidezeit, and T is the abbreviation for the Tertiary Period (a historical term for the period of time now covered by the Paleogene and Neogene periods). The event marks the end of the Mesozoic Era and the beginning of the Cenozoic Era.[1] "Tertiary" being discouraged as a formal time or rock unit by the International Commission on Stratigraphy, the K-T event is now called the Cretaceous—Paleogene (or K-Pg) extinction event by many researchers.

Non-avian dinosaur fossils are only found below the K–T boundary and became extinct immediately before or during the event. A very small number of dinosaur fossils have been found above the K–T boundary, but they have been explained as reworked, that is, fossils that have been eroded from their original locations then preserved in later sedimentary layers. Mosasaurs, plesiosaurs, pterosaurs and many species of plants and invertebrates also became extinct. Mammalian and bird clades passed through the boundary with few extinctions, and evolutionary radiation from those Maastrichtian clades occurred well past the boundary. Rates of extinction and radiation varied across different clades of organisms.

Scientists theorize that the K–T extinctions were caused by one or more catastrophic events such as massive asteroid impacts or increased volcanic activity. Several impact craters and massive volcanic activity in the Deccan traps have been dated to the approximate time of the extinction event. These geological events may have reduced sunlight and hindered photosynthesis, leading to a massive disruption in Earth's ecology. Other researchers believe the extinction was more gradual, resulting from slower changes in sea level or climate.”

Answer 3

The evidence for an asteroid impact (outlined in other answers) is overwhelming. What the debate is about is whether or not the asteroid was enough to finish the dinosaurs off. There was an immense amount of volcanism in India at the time as well, which may have helped. Look up the Deccan Traps.

Answer 4

it was the asteriod because when the asteriod crashed, the weather changed. The pland eating dinosaurs died, and then the meat eating ones died also.  

Answer 5

No I don't  think it was an asteroid i think it was because earth was changing and getting more modern and was harder for them to live without their needs and in this ever changing world they could'nt.

Answer 6

probably was an asteroid which caused all non-avian dinosaurs to go extinct.Those that remain had to live in a world where almost everything is dead and the debris blocked out the sun which caused caused all the plants to die. So with lack of plants, there would be a lack of herbivores, or prey, and without prey, their would be no carnivores and considering that the asteroid killed everything, there would be a lack of food and any surviving non-avian dinosaur would have starved to death.

Answer 7

Evidence that a giant asteroid impact was the cause of the dinosaurs' demise first emerged in the 1980s. Scientists analysing ancient soils in Italy found that layers of clay from the end of the Cretaceous period, the time the dinosaurs vanished, were unusually rich in a heavy metal called iridium. Later evidence of the layer was found in other countries, including Denmark and New Zealand. The most likely cause was believed to be an extraterrestrial rock that struck Earth and showered iridium across the continents. Such an impact would have had a devastating affect on life, as hot rocks fell from the skies and dust shrouded the sun.  

Answer 8

yes