Rocks: Mineral Mixtures

Understanding RockRock-a solid mixture of crystals of

one or more minerals. -Rocks are very useful.

Rock Cycle-The process by which one rock type changes into another.

The Rock Cycle

The Rock Cycle Cont.

Rock ClassificationComposition-the minerals a rock is

made of.

Texture-determined by the sizes, shapes, and positions of the grains of which it is made.

Igneous Rock Igneous comes from the Latin word

for “fire”. It is made by Temperature,

Pressure, and Composition.

Intrusive Igneous Rock When magma cools beneath the

Earth’s surface. It has a coarse-grained texture.

Extrusive Igneous Rock Igneous Rock that forms on the

Earth’s surface.

Sedimentary RockWind, water, ice, sunlight, and

gravity all cause rock to weather into fragments.

Erosion is the process when rocks fragments are moved.

Layers of sediment become compressed and cemented over time.

Dissolved minerals separate out of the water and form a natural glue that will bind the sediments together.

Sedimentary rocks are formed near the Earth’s surface, with little heat and pressure.

Categories of Sedimentary Rocks

Clastic-when rock or mineral fragments, called clasts, stick together.

Chemical-forms when minerals crystallize out of a solution (sea water) and become rock.

Organic-form from the remains of animals.

Metamorphic RockRock that forms when the texture

and composition of pre-existing rock changes due to heat and pressure.

Origins of Metamorphic Rock

The texture can change when the surroundings change.

Most change by pressure that occurs at depths greater than 2 km (about 6000 ft.)

The temperature range is 50 C to 1000 C (122 to 1832 F)

Contact Metamorphism-when the rock comes in contact with magma.

Regional Metamorphism-when a lot of pressure builds up in rocks buried in the Earth or when large pieces of the Earth’s crust collide with each other.

Textures of Metamorphic Rock

Foliated Metamorphic Rock-contains mineral grains that are aligned by pressure.

Non-foliated Metamorphic Rock-the texture of metamorphic rock which mineral grains show no alignment.