Earth Sciences 1022A/B Lecture Notes - Lecture 8: Nonconformist, Oldest Dated Rocks, Relative Dating

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

Document Summary

Relative time: tells us whether a rock is younger or older than another based on: Superposition: each bed is older than the one above, and younger than the one below . In undeformed, horizontal sedimentary rocks, a (youngest on top, oldest on bottom) Original horizontality: layers of sediment is usually deposited horizontally position. A fault must be younger than the rock it cuts. A rock must be younger than the rock it cuts. Inclusions: inclusions within a rock must be older than the rock containing them. Unconformities: missing rocks (due to nondeposition or erosion) within rock sequences: Angular unconformity: (we can usually see in the field) between flat and tilted, eroded beds. Disconformity: between parallel beds, hard to see time break (tough to see in field, can tell things are missing with looking to see if fossils are missing from rocks)