How are rocks different How are rocks different from minerals?from minerals?

Definition of Mineral:Definition of Mineral:

1. Naturally occurring

2. Solid substance

3. Orderly crystalline structure

4. Definite chemical composition

5. Inorganic

Rocks Tell Stories Records of Geologic Past

1. Igneous rocks … from cooling and solidification of lava or magma

2. Sedimentary rocks … from compacted and cemented sediments, or chemical precipitates or evaporites

3. Metamorphic rocks … meta (change) morphic (form) … rocks changed by heat and pressure –but remain solid

Rock Classification – 3 major groups based on their methods of

formation or origin

ESRT – Page 6

IgneousIgneous- rocks that form when molten - rocks that form when molten magma solidifies.magma solidifies.

Lava-magma that reaches the Earth’s surface.

Magma-liquid rock deep within the Earth.

• Intrusive- igneous rocks which form when magma solidifies deep underground.(plutonic)

• Extrusive- igneous rocks which form when lava cools rapidly at Earth’s surface. (volcanic)

FelsicFelsic-lava that is rich in silica, light -lava that is rich in silica, light in color and low density.in color and low density.

MaficMafic-lava that is rich in iron & -lava that is rich in iron & magnesium, dark in color, & high magnesium, dark in color, & high densitydensity

FELSIC

MAFIC

TextureTexture-the size of the mineral -the size of the mineral grains or crystals. (glassy, grains or crystals. (glassy, fine, course)fine, course)

PorphyryPorphyry- a rock that contains a - a rock that contains a mixture of various sized mixture of various sized crystals.crystals.

Igneous Rocks

IGNEOUS ROCKS

Types of Igneous Rock

Type of Texture

Where & How they cool

IGNEOUS ROCKS

Intrusive Extrusive

coarse Very coarse

Vesicular/Non

FineGlassy

Magma cools slowly inside

the earth

Lava cools rapidly at the

Earth’s surface

Non-Vesicular

Type of Igneous Rock

Where & how they cool

Type of Texture

Sedimentary Rock Sedimentary Rock VocabularyVocabulary•ClasticClastic – rocks made up of fragments of other rocks. – rocks made up of fragments of other rocks.

•BioclasticBioclastic- rock formed from the remains of living - rock formed from the remains of living organisms.organisms.

•LithificationLithification- the process of forming a rock.- the process of forming a rock.•Cementation-Cementation- the process of sediments being the process of sediments being

stuck together by minerals in running water.stuck together by minerals in running water.•Compaction-Compaction-process in which air and water are process in which air and water are squeezed out of sediments, forming a sed. rock.squeezed out of sediments, forming a sed. rock.•Precipitation (from solution)- Precipitation (from solution)- when water evaporates when water evaporates and leaves behind the minerals that were dissolved and leaves behind the minerals that were dissolved in the water. in the water.

Sedimentary Rocks

Hints/Clues to look for

TYPES OF

How they formed (method of lithification)

Grain Sizes

Sedimentary

ClasticBioclastic(Organic)

Crystalline(Chemical)

Minerals are dissolved intowater, then the water

evaporates and leaves the minerals behind

Fragments of rocks and organic material

compacted & cementedtogether

Fragmentsof rocks compacted

and cemented together

Pebbles, cobbles,Boulders (mixed)

sand

silt

clay

fossils ofplants or animals Large crystal

Hints/Clues to look for

How Formed (method of Lithification)

Grain Sizes

Metamorphic Rock Metamorphic Rock VocabularyVocabulary

• Recrystallization- the repeated process of melting and solidifying magma into crystals.

• Foliation- a metamorphic rock with visible parallel bands of minerals.

• Regional metamorphism- metamorphism that affects rocks over large areas at tectonic plate boundaries. (heat & pressure)

• Contact metamorphism-metamorphism of a rock due to the extreme heat of contact with magma.

METAMORPHIC ROCKS

Grain Size

Type of Metamorphism

Type of Texture

METAMORPHIC ROCKS

Regional Metamorphism

Contact Metamorphism

Foliated Nonfoliated

CoarseFine MEDIUM Medium CoarseFine

Occurs over a very large area (thousands of Km’s) during tectonic activity. The

movement of tectonic plates creates tremendous heat and pressure at plate boundaries causing the rocks to change

Hot magma pushes through existing rock. The heat from the magma can change the structure

and composition of the existing rock.

Type of Metamorphism

Type of Texture

Grain Size