Explain fossil dating

08 Sep

There are several different methods for estimating the ages of fossils, including: Paleontologists rely on stratigraphy to date fossils.Stratigraphy is the science of understanding the strata, or layers, that form the sedimentary record.The Law of Superposition, which states that older layers will be deeper in a site than more recent layers, was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.The regular order of occurrence of fossils in rock layers was discovered around 1800 by William Smith.From top to bottom: Rounded tan domes of the Navajo Sandstone, layered red Kayenta Formation, cliff-forming, vertically jointed, red Wingate Sandstone, slope-forming, purplish Chinle Formation, layered, lighter-red Moenkopi Formation, and white, layered Cutler Formation sandstone.Picture from Glen Canyon National Recreation Area, Utah.In a way this field, called geochronology, is some of the purest detective work earth scientists do.

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In an undisturbed sequence of rocks, such as in a cliff face, it is easy to get a rough idea of the ages of the individual strata – the oldest lies at the bottom and the youngest lies at the top.

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

So, when looking at the history of a cliff face, it is important to read the story it tells from the bottom layer up.

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.