Relative age dating geologic cross sections

16 Aug

Geologic time covers the whole sweep of earth's history, from how and when the earth first formed, to everything that has happened on, in, and to the planet since then, right up to now.

Geologists analyze geologic time in two different ways: in terms of relative geologic age, and in terms of absolute (or numeric) geologic age.

First is the Law of Superposition - which states that in a section of horizontal strata, the top layer is the youngest and the underlying layers are increasingly older with depth.

The second is the Law of Cross-cutting - meaning anything cutting across another feature is younger than the feature it cuts.

Relative geologic age is established, based on such evidence as the order in which layers of sediment are stacked, with the younger layer originally on top.

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In other words, these relationships have various scales.

Make sure to include when erosion and deformation occurred.

When you are finished check your work with the answers provided.

Below are two cross sections for use practicing the application of the principles of relative age dating.

For each cross section list the order of events that occurred to form the rocks illustrated.