Dating relative rock
The lower sandstone layer is disrupted by two faults, so we can infer that the faults are younger than that layer.
But the faults do not appear to continue into the coal seam, and they certainly do not continue into the upper sandstone.
The principle of inclusions states that any rock fragments that are included in rock must be older than the rock in which they are included.The tilted rocks at the bottom are part of the Proterozoic Grand Canyon Group (aged 825 to 1,250 Ma).The flat-lying rocks at the top are Paleozoic (540 to 250 Ma).The lava flow took place some time after the diorite cooled, was uplifted, and then eroded.(Hammerhead for scale) [SE]Figure 8.6b Rip-up clasts of shale embedded in Gabriola Formation sandstone, Gabriola Island, B. The pieces of shale were eroded as the sandstone was deposited, so the shale is older than the sandstone.