How are the laws of superposition and crosscutting relationships used to determine the relative ages of rocks?
1 Answer
Dec 7, 2016
The law of superposition and crosscutting help to establish relative ages of the rock strata.
Explanation:
The law of superposition logically states that the strata at a lower level is older than the strata above it.
The cross cutting is younger than the strata that it cuts through. If the cross cutting is "cut" off at an higher level it indicates a period of erosion.
However in many cases it is the fossils ( especially index fossils) that determine the relative age of the strata. Explanations are created to explain how fossils thought to be younger end up under strata with fossils that are thought to be older.
