GEOL 1001 Chapter : Chapter 10 - Relative & Absolute Time
Document Summary
Part 1 - relative time - the age of one feature with respect to another in a sequence. Part 2 - absolute time (numerical age) - the age of a feature given in years. Learning objective 1: principles that allow us to determine relative age. The present is the key to the past. Observe geologic processes today, look at rock record and determine geologic history. If you see tilted rocks, then they must be deformed: principle of superposition. Layers that are on the bottom are older than those on top. Work for sedimentary rocks and extrusive igneous (volcanic) rocks: principle of lateral continuity. Allows us to correlate units that are far apart: principle of cross-bedding relationships. If one geologic feature cuts another, the one being cut is older: principle of baked contacts. The rock that has been baked is older than the intrusion: principle of inclusions. Any rock that contains an inclusion, must be younger than the inclusion.
