Final answer:
Using unconformity bounded sequences as a correlation tool involves comparing rock layers for similar patterns and utilizing fossil assemblages to determine age equivalency and sedimentary history.
Step-by-step explanation:
The concept of using unconformity bounded sequences of rocks as a correlation tool involves the recognition that an unconformity is a boundary between two strata of differing ages indicating an interruption in sedimentation, usually caused by erosion. When correlating rock layers over distances, geologists look for similar patterns in rock outcrops - a method known as lithostratigraphic correlation.
Additionally, fossils provide valuable information through biostratigraphic correlation, where similar fossil assemblages can confirm that different rock layers were deposited at the same time despite differing sediment types like sandstone and shale.