1. Table of Contents
Chapter 4: Rocks
Section 4.1: The Rock Cycle

2. The Rock Cycle 1
The Rock Cycle
The rock cycle shows the three types of rock— igneous, metamorphic, and sedimentary—and the processes that form them.
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3. Igneous Rocks 2
Magma
Because (2) magma is less dense than surrounding solid rock, it is forced upward toward the surface.
When magma reaches Earth’s surface and flows from volcanoes, it is called lava.
The difference between magma and lava is location: magma underground and lava on surface

4. Texture
(3) Texture refers to the size of a rocks mineral grains. (4) coarse—large mineral grains fine---small mineral grains glassy—no mineral grains

5. Igneous Rocks 2

6. Question 5 Extrusive Intrusive Formed from lava Formed from magma
Formed on the surface
Cools quickly
Fine or glassy texture
Small grains or no grains
EX: rhyolite Pumice
basalt obsidian
scoria
Intrusive
Formed from magma
Formed underground
Cools slowly
Coarse texture
Large mineral grains
EX: granite
gabbro

7. Classifying Metamorphic Rocks3
Classifying Metamorphic Rocks
Heat, pressure, and hot fluids trigger the changes.
Each resulting rock can be classified (7) according to its composition and texture.

8. Question 8 Foliated Has visible layers EX: gneiss slate schist
Nonfoliated
Does not have visible layers
EX: marble
quartzite

9. Question 9 Igneous to metamorphic Granite --- gneiss Basalt --- schist
Sedimentary to metamorphic
Shale --- slate
Sandstone ---- quartzite
Limestone --- marble
Metamorphic to metamorphic
Slate --- phyllite

10. Formation of Sedimentary Rocks4
Formation of Sedimentary Rocks
(11) Igneous rocks are the most common rocks on Earth, but because most of them exist below the surface you might not have seen too many of them.
75 percent of the rocks exposed at the surface are sedimentary rocks.

11. Formation of Sedimentary Rocks4
Formation of Sedimentary Rocks
Sediments come from (12) already-existing rocks that are weathered and eroded.
Sedimentary rock forms when sediments are pressed and cemented together, or when minerals form from solutions.

12. Classifying Sedimentary Rocks4
Classifying Sedimentary Rocks
Like igneous and metamorphic rocks, sedimentary rocks are classified (13) by their composition and by the manner in which they formed.

13. Weathering and Erosion
Sedimentary Rocks 4
Weathering and Erosion
When rock is exposed to air, water, or ice, it breaks down chemically and mechanically.
(14) weathering is the process which breaks rocks into smaller pieces.
These pieces are classified by size.
erosion is the movement of weathered material

14. Sedimentary Rocks 4
Compaction

15. Sedimentary Rocks 4
Cementation

16. (15) Detrital (Clastic) Chemical
Formed from rock sediments on the surface
Formed by compaction and cementation
EX: Sandstone, shale
conglomerate,breccia
Chemical
Formed by precipitation of minerals or evaporation of water.
EX: Limestone

17. (15) Organic Formed from remains of living things
Formed by compaction and cementation
EX: coal, shell limestone