Relative dating erosion
To determine the nature of the contact - whether it is an intrusive contact or a nonconformity - further evidence from field investigations would be needed.
Evidence such as angular pieces of conglomerate surrounded by the granitic intrusion, and contact metamorphism of the conglomerate adjacent to the granite, would indicate that the granite is younger and intruded the older conglomerate.
The key to identifying each specific type of unconformity is recognizing what the unconformity is on top of.
The possibilities for what is in the rocks immediately beneath the unconformity are (1) layers of sedimentary or volcanic rock (strata) that have been tilted or folded prior to development of the unconformity; (2) a stratum is parallel to the unconformity and parallel to the stratum above the unconformity; or (3) plutonic or metamorphic rocks, which originated much deep in the earth's crust rather than at its surface.
They are summarized as the Principles of Relative Geologic Age Determination, sometimes referred to as the Principles of Relative Dating.In the 20th century, radiometric methods of absolute age determination were developed.