Final answer:
The Principle of association in stratigraphy uses laws such as the law of superposition, the principle of original horizontality, the principle of lateral continuity, and the principle of cross-cutting relationships to determine the relative ages of rock layers.
Step-by-step explanation:
The principle of association in stratigraphy uses various laws to determine the relative ages of rock layers and their fossil contents. Three fundamental laws include:
- The law of superposition, posits that in undisturbed horizontal sedimentary rock layers, the oldest layer is at the bottom and the youngest is at the top.
- The principle of original horizontality, suggests that layers of sediment are originally deposited horizontally and that any tilting or folding must have occurred after deposition.
- The principle of lateral continuity, which states that layers of sedimentary rocks originally extended in all directions until they thinned out or were truncated by other geological features.
Another law is the principle of cross-cutting relationships, indicating that geologic features that cut through rocks must have formed after the rocks they cut through. This allows geologists to create a relative chronological sequence of events. Through the combination of these principles, geologists and archaeologists can interpret the earth's history recorded in the rock strata and the fossils within them.