Cross-cutting relationships among geological features have been recognized for many years as one of the fundamental ways of determining relative age relationships between adjacent geological features. The principle of cross-cutting relationships, explained by James Hutton (1726–1797) in Theory of the Earth (1795) and embellished upon by Charles Lyell (1797–1875) in his Principles of Geology (1830), holds that the geological feature which cuts another is the younger of the two features. For example, in the instance of an igneous dike cutting through a layer of sandstone, the dike must be younger than the sandstone.

Cross-cutting relationships are of several basic types. There are structural cross-cutting relationships wherein a fault or fracture cuts through older rock. Stratigraphic cross-cutting relationships occur where an erosional surface (or unconformity) cuts across older rock layers, geological structures, or other geological features. Sedimentologic cross-cutting relationships occur where currents have eroded or scoured older sediment in a local...