Which metallic element is commonly associated with the doomsday asteroid believed to have wiped out the dinosa

Answer 1

Iridium (IPA: /ɪˈɹɪdiəm/) is a chemical element in the periodic table that has the symbol Ir and atomic number 77. A dense, very hard, brittle, silvery-white transition metal of the platinum family, iridium is used in high strength alloys that can withstand high temperatures and occurs in natural alloys with platinum or osmium. Iridium is notable for being the most corrosion resistant element known and for its significance in the determination of the probable cause of the demise, by a meteorite strike, of the dinosaurs. It is used in high temperature apparatus, electrical contacts, and as a hardening agent for platinum.

Answer 2

Iridium.

There is a good discussion of the event which left a mark on the earth as the Chicxulub Crater in wikipedia, the free online encyclopedia:
http://en.wikipedia.org/wiki/Chicxulub_Crater

A quote from this web site:

"This timing is in good agreement with the theory postulated by the physicist Luis Alvarez and his son Walter, a geologist, for the extinction of the dinosaurs. The Alvarezes postulated that the extinction of the dinosaurs, roughly contemporaneous with the K-T boundary, could have been caused by the impact of just such a large meteorite. This theory is now widely, though not universally, accepted by the scientific community. [2] The main evidence is a widespread, thin layer of clay present in this geological boundary across the world. In the late 1970s the Alvarezes and colleagues reported [3] that it contained an abnormally high concentration of iridium – 6 parts per billion by weight or more compared to 0.4[4] for the Earth's crust as a whole — meteorites can contain around 470 parts per billion[5] of this element. It was hypothesised that the iridium was spread into the atmosphere when the meteorite was vapourised and settled across the Earth's surface amongst other material thrown up by the impact, producing the relatively iridium-rich layer of clay[6]"

Hope this helps!

Answer 3

Iridium. It was the presence of an increased amount of Iridium in rock layers dating back to about 65 million years ago from many parts of the earth, coinciding with the fossil record's evidence that this was the same time the dinosaurs became extinct that prompted Louis Alvarez to first hypothesize the collision of an asteroidal or cometary body with the earth.

Answer 4

Iridium

Answer 5

Iron.