Rock & Relative Dating Reinforcement

Vocabulary 1. A (metamorphic rocks) 2. H (rock) 3. N (igneous rocks) 4. D (sedimentary rocks) 5. J (extrusive igneous rock) 6. P (compaction)

7. E (lava) 8. R (intrusive igneous rocks) 9. L (sediments) 10. B (rock cycle) 11. G (cementation) 12. F (law of superposition)

15. S (uniformitarianism) 13. I (law of original horizontality) 14. K (unconformity) 15. S (uniformitarianism) 16. Q (principle of inclusion) 17. M (law of cross cutting) 18. C (relative dating) 19. O (catastrophism)

Understanding Concepts 1. Describe how the following types of rocks are formed: a. Igneous: igneous rock is formed when lava rises to the earth’s surface and cools or magma cools below the earth’s surface.

1 b. Sedimentary: sedimentary rocks are made from sediments of other rocks or organic material that are compacted & cemented together.

1 c. Metamorphic: form from changes in igneous, sedimentary, or other metamorphic rocks that have been exposed to heat, pressure, and/or hot fluid activity.

2. Use the rock cycle to describe two different ways magma can become metamorphic rock. 1. Magma can cool to become igneous rocks. Heat & pressure can turn igneous rocks into metamorphic rock.

2. Continued… 2. Magma can cool to become igneous rocks. Weathering & erosion turn igneous rocks to sediments. Sediments are compacted to form sedimentary rocks. Heat & pressure can turn sedimentary rock into metamorphic rock.

The Rock Cycle Lava, Magma

3. The diagram shows the three types of rock and processes that form them. This process is called the _________. rock cycle

magma 4. Lava and _______ can cool to become igneous rocks. 5. Heat and pressure can turn sedimentary or _______ rocks into metamorphic rocks. igneous

6. Metamorphic rock can _____ , then cool to become igneous rock. 7. Weathering & erosion break igneous and other types of rock into smaller pieces called _________ . melt sediments

8. For the following rock types, what are some of the characteristics you could use to identify each type of rock? a. Igneous: may have small or large crystals that are not flattened, may appear glassy, or may have holes or spaces in the rock

8 b. Sedimentary: may look grainy, can have pieces of other rocks, can have fossils, or can have distinct parallel layers 8 c. Metamorphic: may be shiny, can have colored layers but will be thin and wavy, or may have thin or flattened crystals

9. If horizontal layers of sedimentary rock have a vertical fault running through them, how might a geologist use relative dating to determine when the fault occurred . A geologist could use the law of cross-cutting relationships. The fault would be younger than any rock layer it cuts across, and older than any rock it DOES NOT cut across.

Old – E, D, C, F, B, Fault, A – Young 10. List events A-F in the order they occurred, beginning with the oldest event. Old – E, D, C, F, B, Fault, A – Young

11. When did the fault occur? How do you know this? The fault occurred after rock layer E, D, F & B (must be younger because it is cutting across these layers), but is older than A (because not cutting across A). We know this because of the law of cross-cutting relationships.