In order to view this website you need to update your internet browser. If an igneous rock, a fault, or an unconformity is truncated by ends at an unconformity, you may assume that the truncated feature once extended farther, and was eroded when the unconformity was formed. Find out more Accept. The earlier sequence of rock formations had to have been tilted before the more recent sequence of rock formations was deposited on top of it. The tilting must have occurred between these two times. Just as Sherlock Holmes used his power of observation to decipher the clues to a suspect's past actions, we will let the blemishes and behaviors of the rocks tell us their past story. As geologists piece together the information at various outcrops, they can begin to assemble a "geologic map" like a road map of an entire region consisting of many square miles.
Willard libby developed radiocarbon dating practice with answers, geologists are able to interpret geological cross section 1.
Geologic Time Activities
Cliffs and road cuts are "side views" or "geologic cross-sections" of the topography which show the relative positions of various rock layers and structures at a given spot. Find the youngest layer which has been tilted and the oldest layer which has NOT been tilted. Start studying relative dating exercises. The previous layers are eroded off at the top too. Or, let your students choose the one that makes the most sense to them. Surfaces O and P are faults - breaks in the rocks along which motion has occurred during earthquakes. Give each student a geologic event with its age and have them stand at the appropriate distance from "present day".