PreQuizPreQuiz

1. Describe the strength of bonds between atoms in a solid.

2. What is a mineral?

3. True or False: Only eight elements make up the bulk of the minerals found in Earth’s crust.

4. What is the most common mineral group?a. carbonates b. silicates c. oxides d. halides

5. What are rock-forming minerals?

6. What are some common properties of minerals?

3.1 The Rock Cycle3.1 The Rock Cycle

• rock- any solid mass of mineral or mineral-like matter that occurs naturally as part of our planet– Mixtures of minerals and sometime

nonmineral material

• 3 major types of rocks:– Igneous– Sedimentary– metamorphic

Rock CycleRock Cycle

Summary QuestionsSummary Questions• Use your own words to describe the sequence of

processes that result in igneous rocks. Describe a specific example of a sedimentary rock becoming an igneous rock.

• Use your own words to describe the sequence of processes that result in sedimentary rocks. Describe a specific example of a sedimentary rock becoming a new type of sedimentary rock.

• Use your own words to describe the sequence of processes that result in metamorphic rocks. Describe a specific example of a sedimentary rock becoming a metamorphic rock.

Igneous RocksIgneous Rocks• Formation

– Intrusive Igneous Rocks• Rocks that form when magma hardens beneath

Earth’s surface– Magma- molten material below earth’s surface

– Extrusive Igneous Rocks• Rocks that form when lava hardens on Earth’s

surface– Lava- molten material on or above earth’s surface

granite rhyolite

Texture of Igneous RocksTexture of Igneous Rocks

• Igneous Rocks are classified by texture and composition

• Textures– Coarse-grained- slow cooling results in large crystals– Fine-grained-rapid cooling results in rocks with small,

interconnected mineral grains– Glassy- cools so quickly that ions cannot arrange

themselves into a network of crystals • Glassy does not mean they look glassy!!! (pumice)

– Porphyritic- rocks experience different rates of cooling, so they have different sizes of crystals in the same rock

Igneous TexturesIgneous Textures

Coarse-grained

Fine-grained

Glassy

Porphyritic

Examples of Igneous RocksExamples of Igneous Rocks

1. Granite

2. Rhyolite

3. Gabbro

4. Basalt

5. Obsidian

6. Pumice

Sedimentary RocksSedimentary Rocks• Formation (5 major processes)

– Weathering- breaks rocks into sediments• Sediments- smaller pieces of rocks and minerals

– Erosion- movement of sediments• Agents: water, wind, ice, or gravity

– Deposition- dropping of sediments because agent lost energy

– Compaction- squeezing or compacting of sediments

– Cementation- dissolved minerals are deposited in the tiny spaces among the sediments

Classification of S.R.Classification of S.R.• Classified according to the way they form

– Clastic sedimentary rocks- made of weathered bits of rocks and minerals

• Grouped according to the size of the sediments– Conglomerate- rounded, gravel-size or larger– Breccia- angular

– Chemical sedimentary rocks- forms when dissolved minerals precipitate from water solutions

Features of S.R.Features of S.R.

• The many unique features of sedimentary rocks are clues to how, when, and where the rocks formed– Layers show the order in which the rocks

formed– Fossils hidden in sedimentary rocks show

evidence of past life forms– Ripple marks and mud cracks

Examples of S.R.Examples of S.R.

• Conglomerate

• Breccia

• Sandstone

• Limestone

• Rock salt

Metamorphic RocksMetamorphic Rocks

• Metamorphism- to change form• Formation

– Changes occur at elevated temperatures and pressures

– Conditions are found a few kilometers below Earth’s surface and extend into the upper mantle

• Agents– Heat- provides energy needed to drive chemical

reactions, which may cause minerals to recrystallize– Pressure- may cause the spaces between mineral

grains to close or cause the mineral to recrystallize– Hydrothermal Solutions- hot water solutions

promote recrystallization by dissolving original minerals and then depositing new ones

Classification of M.R.Classification of M.R.

• Classified by texture and composition

• Texture– Foliated-rocks with layered or banded

appearances• Formed when rocks undergo intense pressures

causing the rock to be more compact or even recrystallize the rock

– Nonfoliated- rocks without banded appearances

• Contain only one mineral

Contact vs. RegionalContact vs. Regional

• Contact Metamorphism– When magma intrudes rock– Produces low-grade metamorphism = minor

changes• Ex: Marble

• Regional Metamorphism– During mountain building, rocks are exposed to

extreme pressures and temperatures – Produces high-grade metamorphism = intense

changes

Examples of M.R.Examples of M.R.

• Parent rock- original rock before metamorphism takes place

Metamorphic Rock

Parent Rock

Slate Shale

Gneiss Schist, Granite

Marble Limestone

Quartzite Sandstone

Schist Phyllite

Anthracite Bituminous Coal