Start Three rules of relative dating

Three rules of relative dating

The Grand Canyon is particularly good for this because different sedimentary rocks have different colors.

Principle of Uniformitarianism The principle of Uniformitarianism was postulated by James Hutton (1726-1797) who examined rocks in Scotland and noted that features like mudcracks, ripple marks, graded bedding, etc.

where the same features that could be seen forming in modern environments.

Once these age relations were worked out, another principle fell into place - the principle of fossil succession.

We discuss the 7 principles of stratigraphy first and then see how these apply to fossils.

He concluded that process that are currently operating on the Earth must be the same processes that operated in the past.

This principle is often stated as "the present is the key to the past".

Principles of Stratigraphy Stratigraphy is the study of strata (sedimentary layers) in the Earth's crust.

Geologist in the 1800s worked out 7 basic principles of stratigraphy that allowed them, and now us, to work out the relative ages of rocks.

Thus, we can deduce that the mudstone and shale are older than the rhyolite dike.

But, since the rhyolite dike does not cut across the shale, we know the shale is younger than the rhyolite dike.

Thus, we know that the dike is younger than the mudstone, sandstone, and shale.