Why is iridium so useful in determining that an asteroid crashed into the Earth 65 million years ago?

One particular heavy element, iridium, is much more abundant in comets and asteroids than it is in Earth’s crust, and thus is useful in determining if an object from space hit Earth.

Why is iridium found in asteroids?

Why is the element iridium found much more abundantly in asteroids than on earth? – Quora. Because it is very dense, and bonds well with iron. As a result, almost all of the iridium on Earth sunk down into the core while our planet was still molten, just after its formation.

Why does the abundance of iridium suggest that the iridium came from an impact quizlet?

Why does the abundance of iridium suggest that the iridium came from an impact? Iridium is rare on Earth’s surface but common in meteorites that have impacted the Earth. It seems unlike that we would have evolved by now without the extinctions caused by the impact.

What is the concentration of iridium in the iridium layer?

Iridium concentrations are highest in the spinel-bearing spherules (up to >100 ppb) and lower in the nonspinel bearing spherules and surrounding clay (1 to 10 ppb) (11, 14, 43). Rocchia et al.

How far down is the iridium layer?

3-4 cm
The thickness of the layer appeared to be 3-4 cm. The iridium-rich layer at the K-T Boundary has been associated with the Chicxulub Crater centered off the Yucatan Peninsula of Mexico, for which a strong case has been made for an asteroid impact that contributed to the observed mass extinction.

Why does the abundance of iridium suggest that the iridium come from an impact?

What would happen if a 1 km object struck Earth?

What would happen if a 1-kilometer object struck Earth? It would cause widespread devastation and climate change. What do asteroids and comets have in common? What is the size of the largest asteroid?