Horny chatting websites free for iphone - Methods for dating fossils

The sediment of this area was laid down after ammonite A appeared 199 million years ago, and before ammonite B became extinct 195 million years ago.

This narrows the date of the delta beds to the four million years between these dates.

There are some radioactive elements in rock that decay by giving off energy and turning into different, more stable elements.

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The Age of Dinosaurs was so many millions of years ago that it is very difficult to date exactly.

Scientists use two kinds of dating techniques to work out the age of rocks and fossils. This considers the positions of the different rocks in sequence (in relation to each other) and the different types of fossil that are found in them.

When someone mentions scientific dating methods, the first thing to come to mind for most people is carbon dating.

However, there are many methods that can be used to determine the age of the earth or other objects.

Ammonites, shelled relatives of today’s octopus, make ideal index fossils.

Suppose a dinosaur fossil has been found in the beds of an ancient delta (the mouth of a river leading to the sea).

Sometimes, scientists already know the age of the fossil because fossils of the same species have been found elsewhere and it has been possible to establish accurately from those when the dinosaur lived.

Geologists call this the principle of lateral continuity.

This is because new sediments are always laid down on top of sediments that have already been deposited.

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