3 chapter 3 types of:. rocks rocks are any solid mass of mineral or mineral-like matter occurring...
TRANSCRIPT
Chapter
33 TYPES OF:
Rocks
Rocks
Rocks are any solid mass of mineral or mineral-like matter occurring naturally as a part of our planet.
Types of Rocks
• The 3 kinds of rocks are igneous, sedimentary, and metamorphic
Igneous Rocks
• formed by the crystallization of molten magma or lava.
• Magma is molten material deep beneath the Earth’s surface
• Lava is molten material above the surface
Types of Igneous Rocks
1. Intrusive igneous rocks are formed when magma hardens beneath Earth’s surface.
2. Extrusive igneous rocks are formed when lava hardens (above the Earth’s surface).
1. Texture
Igneous rocks can be classified based on their composition and texture.
• Coarse-grained texture is caused by slow cooling resulting in larger crystals.
• Fine-grained texture is caused by rapid cooling resulting in smaller, interconnected mineral grains.
How Igneous Rocks are Classified
• Glassy texture is caused by very rapid cooling.
Course-Grained Igneous Texture
Granite
Fine-Grained Igneous Texture
Rhyolite
Obsidian Exhibits a Glassy Texture.
2. Composition• What the rock is made of, based on the
amounts of light and dark minerals in the rock.
Porphyritic Igneous Texture
Basalt
Classification of Igneous Rocks
Formation of Sedimentary Rocks
Sedimentary Rocks
• Erosion involves the weathering and the removal of rock.
• Deposition occurs when an agent of erosion—water, wind, ice, or gravity—loses energy and drops sediments.
Sedimentary Rock Formation
• Compaction is a process that squeezes, or compacts, sediments.
• Cementation takes place when dissolved minerals are deposited in the tiny spaces among the sediments.
3 Types of Sedimentary Rock
• Clastic – composed of weathered bits of rocks and minerals– Classified by particle size– Ex: Shale, Sandstone, Conglomerate, Grand
canyon & the wave in Arizona
Shale with Plant Fossils
Sandstone
Conglomerate
The Wave, Page, AZ
Grand Canyon, Arizona
• Chemical – When minerals dissolve out of water– Ex: limestone (caves), coal, rock salt
Fossiliferous Limestone
Carlsbad Caverns, NM
Stalactites
Stalagmites
• Organic – Formed by fossils or organic matter within the rock layers
Classification of Sedimentary Rocks
Formation of Metamorphic Rocks
Metamorphic Rocks
Metamorphism means “to change form.”
Igneous and sedimentary rocks change at elevated temperatures and pressures deep within the Earth or during mountain building
Agents of Metamorphism
Heat
Pressure
• Provides the energy needed to drive chemical reactions
• Causes a more compact rock with greater density
Origin of Pressure in Metamorphism
• Hot water-based solutions escaping from magma
• Dissolves original minerals and then deposits new ones
Hydrothermal Solutions
Classifying Metamorphic Rocks
1. Foliated Metamorphic Rock
2. Nonfoliated Metamorphic Rock
Two main categories
• Has a banded or layered appearance
• Does not have a banded texture
Classification of Metamorphic Rocks
Gneiss Typically Displays a Banded Appearance
Marble—A Nonfoliated Metamorphic Rock
IGNEOUS ROCKS SEDIMENTARY ROCKS
METAMORPHIC ROCKS
Fill in the following table using your textbook (pgs. 71-84)