GEL 20 Lecture Notes - Lecture 3: Radiometric Dating, Erosion Surface, Orogeny
Document Summary
Putting rocks and events in general time order. Painfully obvious principles and how to use them. Calculating numerical ages of rocks and events. Based on radiometric dating (radioactivity in rocks) Relative dating: putting rocks and geologic events in chronological order based on observable physical relationships. Principle of original horizontality : sedimentary particles settle (are deposited) in. Principle of original lateral continuity : sedimentary layers are deposited as ~ Principle of superposition : the oldest sedimentary layers are on the bottom with. Principle of cross-cutting relationships : if one rock type or feature cuts across continuous blankets over broad regions. progressively younger layers above them. another rock type or feature, then the one doing the cutting is younger. Faults are younger than the rocks they cross. Igneous intrusions are younger than the rocks they cross. Principle of inclusions : if one rock type is contained within another rock type, the one inside (the inclusion) is older.
