Earth Sciences 1022A/B Lecture 8: Earth Science Lecture February 2 2016

• School: Western University
• Department: Earth Sciences
• Course: Earth Sciences 1022A/B
• Professor: Stephen R Hicock

Document Summary

Tells us whether a rock is younger or older than another based on: superposition. In undeformed, horizontal sedimentary rocks, a bed is older than the one above and younger than the one below. Oldest on the bottom: original horizontality. Layers of sediment tend to be deposited in a horizontal position: cross-cutting relations. A fault or a rock must be younger than the rock it cuts into: inclusions. Inclusions within a rock must be older than the rock containing them: unconformities. Missing rocks due to erosion or nondeposition with rock sequences. Angular unconformity: flat strata resting on tilted and eroded strata. They are found in between the parallel layers. Nonconformity: commonly flat sedimentary rocks resting on igneous or metamorphic rocks flowing the erosion of lower rocks, correlation. Matching similar rock type, position and fossils in the rock record based on fossil succession as organisms evolved through earth"s history.