Types of RocksTypes of Rocks

Mrs. NegritoMrs. Negrito6th Grade Science6th Grade Science

Chapter 16 Chapter 16 Section 1 & 2Section 1 & 2

RocksRocks

Rock- is a solid mixture of Rock- is a solid mixture of crystals of one or more crystals of one or more minerals. minerals.

Mineral- is naturally Mineral- is naturally formed solid matter with a formed solid matter with a crystal structure. crystal structure.

Rocks are made up of Rocks are made up of minerals.minerals.

Composition- is the rocks Composition- is the rocks make-up.make-up.

Rock ClassificationRock Classification

Igneous- form when Igneous- form when hard, liquid rock cools hard, liquid rock cools and hardens.and hardens.Sedimentary- form Sedimentary- form when rocks are when rocks are broken down into broken down into smaller pieces that smaller pieces that harden.harden.Metamorphic- rocks Metamorphic- rocks heated or squeezed.heated or squeezed.

Granite

Sandstone

Gneiss

TextureTexture

Fine-grained rocks made of small grains. Fine-grained rocks made of small grains.

Coarse-grained rocks made of grains that are Coarse-grained rocks made of grains that are larger than a pebble.larger than a pebble.

Medium- grained texture rocks-between fine and Medium- grained texture rocks-between fine and coarse grained. coarse grained.

Texture of RocksTexture of Rocks

Fine-grained rockBasalt

Coarse-grained rockGranite

Medium-textured rockAndesite

Igneous RocksIgneous Rocks

Composition of lava determines type Composition of lava determines type

of rock.of rock. Form when hot, liquid rock, or Form when hot, liquid rock, or magma, cools to form mineral magma, cools to form mineral crystals. Form deep in the Earth or crystals. Form deep in the Earth or at sites of volcanic activity.at sites of volcanic activity.

Extrusive- magma that reaches the Extrusive- magma that reaches the surface and cools forming rocks such surface and cools forming rocks such as: pumice,basalt, rhyolite, scoria, as: pumice,basalt, rhyolite, scoria, and obsidian, and obsidian,

Igneous Rocks, cont.Igneous Rocks, cont.

Intrusive- Magma Intrusive- Magma that cools before that cools before reaching the reaching the surface. The surface. The longer it cools, longer it cools, the larger the the larger the crystals. crystals. Examples: Examples: Granite,and Granite,and gabbro.gabbro.

Sedimentary RockSedimentary Rock

Form when grains of rock or Form when grains of rock or sediment collect and harden into new sediment collect and harden into new rock. rock.

Composition of rock depends on the Composition of rock depends on the sediment deposit. sediment deposit.

Sediment is cemented together - Sediment is cemented together - Lithification.Lithification.

Examples:Examples: Sandstone, Coquina, Sandstone, Coquina, Shale, Rock Gypsum, Limestone, Shale, Rock Gypsum, Limestone,

Coal,Coal, Conglomerate, Rock Salt.Conglomerate, Rock Salt.

Metamorphic RocksMetamorphic RocksForm when rocks Form when rocks metamorphose or change as metamorphose or change as they are heated or squeezed.they are heated or squeezed.

The texture depends on how The texture depends on how the minerals are arranged. the minerals are arranged.

Rocks made of different Rocks made of different minerals often are foliated or minerals often are foliated or banded.banded.

Non- foliated if fewNon- foliated if few different different minerals.minerals.Examples:Marble and Gneiss. Examples:Marble and Gneiss.

Process that shape the EarthProcess that shape the Earth

Weathering- water, ice and heat break Weathering- water, ice and heat break down the rock into smaller pieces or down the rock into smaller pieces or sediment. sediment.

Erosion- when grains of rock are moved Erosion- when grains of rock are moved from their source.from their source.

Deposition- water, ice, wind or gravity drop Deposition- water, ice, wind or gravity drop newly formed sediment. newly formed sediment.

ErosionErosion