1. Nonconformity - sedimentary rocks over crystalline (metamorphic or igneous) rocks N. Lindsley-Griffin, 1998

2. Nonconformity - sedimentary rocks over crystalline (metamorphic or igneous) rocks N. Lindsley-Griffin, 1998

3. Nonconformity - sedimentary gravels over garnet schist. What is the history of this outcrop? N. Lindsley-Griffin, 1998

4. Nonconformity - sedimentary gravels over garnet schist. What is the history of this outcrop? N. Lindsley-Griffin, 1998

5. Cross-cutting relationships: dike cutting gneiss is younger N. Lindsley-Griffin, 1998

6. Cross-cutting relationships: dike cutting gneiss is younger N. Lindsley-Griffin, 1998

7. Cross cutting relationships: what is the sequence of events in this folded marble with two dikes? N. Lindsley-Griffin, 1998

8. Cross cutting relationships: what is the sequence of events in this folded marble with two dikes? N. Lindsley-Griffin, 1998

9. Superposition Disconformity Original horizontality Angular unconformity Cross-cutting relationships Nonconformity Grand Canyon Formations © Houghton Mifflin 1998. All rights reserved

10. Grand Canyon Formations © Houghton Mifflin 1998. All rights reserved Sequence of events based on geology of the Inner Gorge 1.Deposition of shale in marine environment 2. Metamorphism of shale into Vishnu schist 3. Intrusion by Zoroaster granite 4. Erosion to sea level, unconformity surface 5. Deposition of Grand Canyon Supergroup 6. Faulting 7. Erosion of fault blocks, deposition of Tapeats sandstone

11. Geologic Time - Summary N. Lindsley-Griffin, 1999 Relative Age -- whether a particular rock or feature is older or younger than another Absolute Age -- the age of a rock in years (m.y. = millions of years) Geologic Column -- shows succession of all known strata, in chronological order, based on fossils and other relative ages