Question

How the law of crosscutting relationships helps scientists determine the relative age of rocks?

Answer 1

Hint: To determine the age of a rock , researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events

Complete answer:
- Cross-cutting relationships is a doctrine of geology that states that the geologic trait which cuts another is the younger of the two traits.
- By using the technique superposition and cross-cutting relationships, geologists can deduce relative ages of rocks. This implies that they can determine which rocks are older and which are younger, but not the precise ages of the rocks.
- For example, if a fault were abridged by an unconformity, and that in conformity is slashed by a dike. Based on such combination cross-cutting relationships, it can be recognized that the fault is older than the unconformity which in turn is older than the dike.

Note:
- Danish geological pioneer Nicholas Steno was the first to give the theory of cross-cutting relationships. Later, it was formulated by James Hutton.
- The dating of rocks is important for not only establishing the history of geological occurrences but also for determining the rates of geological processes.
- The igneous rocks are most suitable for dating as compared to metamorphic and sedimentary rocks.