Rock Notes- 3 types of Rock

Rock Notes A) Rock- a mixture of minerals and other materials Mineral- a naturally occurring, inorganic solid with a crystal structure and definite chemical make up The basic building blocks of rocks are minerals.

1) Igneous rock- forms from the cooling of molten rock (magma or lava) B) Rock Classification: Origin- rocks are mainly classified by how they are formed 1) Igneous rock- forms from the cooling of molten rock (magma or lava) Extrusive Rock- igneous rock formed from lava that erupted onto Earth’s surface; basalt is the most common extrusive rock Intrusive Rock- igneous rock that formed when magma hardened beneath Earth’s surface; granite is the most common intrusive rock

Igneous Rocks….. (i) Fine-grained- rapid cooling ©Texture- depends on the size and shape of the mineral crystals (i) Fine-grained- rapid cooling (ii) Glassy- rapid cooling (iii) Coarse, large, or medium grained- slow cooling; the slower magma cools, the larger the crystals

Sedimentary Rock (2) Sedimentary rock- forms when particles of other rocks or the remains of plants and animals are pressed and cemented together Processes that turn sediment to rock (i) Weathering- breaks rock down into sediment (ii) Erosion- moving of sediment to a new location (iii) Deposition- dropping of sediment (iv) Compaction- presses sediment together (v) Cementation- dissolved minerals crystallize and glue particles of sediment together

Types of Sedimentary Rocks (i) Clastic- a sedimentary rock that forms when rock fragments squeeze together like shale, sandstone, and conglomerate (ii) Organic- forms when layers of plants and animals are deposited in thick layers like coal and limestone (iii) Chemical- form when minerals that are dissolved in a solution crystallize or from mineral deposits that are left when seas or lakes evaporate like rock salt

Metamorphic rock Metamorphic rock- formed when an existing rock is changed by heat and/ or pressure (a) Foliated- grains arranged in parallel layers or bands like slate, schist, and gneiss (b) Nonfoliated- mineral grains are arranged randomly like marble and quartzite

Rock Cycle C) Rock Cycle- forces inside the Earth and at the surface produce a rock cycle that builds, destroys, and changes the rock in the crust; the series of processes on and beneath Earth’s surface that slowly change the rock from one kind to another (1) Any rock can change into another type of rock; rocks of the same type can turn into a new rock of that type

Look at these pictures of rocks. How are they different? How are they the same?

ROCKS

IGNEOUS ROCKS GRANITE BASALT CLIFFS GABBRO

HOW ARE IGNEOUS ROCKS FORMED ?

Igneous Rocks – ‘fire rocks’ Igneous rocks are made either underground or above ground.

Igneous Rocks – ‘fire rocks’ Underground: melted rock, called magma, cools slowly and becomes igneous rocks. (Intrusive)

Igneous Rocks – ‘fire rocks’ Above ground: volcanoes erupt, bringing magma to the earth's surface, it is called lava. The lava cools and becomes igneous rocks. (extrusive)

Igneous Rocks – ‘fire rocks’ Granite Basalt Pumice

HOW ARE SEDIMENTARY ROCKS FORMED ?

HOW ARE SEDIMENTARY ROCKS FORMED ?

Sedimentary Rocks – ‘sandwich rocks’ For millions of years, little pieces of our earth (called sediments) have been broken down by wind and water.

Sedimentary Rock – ‘sandwich rocks’ These little bits of our earth are washed to the bottom of the rivers, lakes, and oceans where they settle.

Sedimentary Rock – ‘sandwich rocks’ Many layers of small pieces of earth collect on top of each other in layers. These layers are pressed down more and more until the bottom layers slowly turn into hard rock.

Sedimentary Rock – ‘sandwich rocks’ Limestone Coal Sandstone

SEDIMENTARY ROCKS LIMESTONE CHALK COAL

METAMORPHIC ROCKS MARBLE SLATE GNEISS

HOW ARE METAMORPHIC ROCKS FORMED ?

Metamorphic Rock – ‘changing rocks’ Metamorphic rocks are rocks that have "morphed" or changed into another kind of rock. These rocks were once igneous or sedimentary rocks.

Metamorphic Rock – ‘changing rock’ Millions of tons of heat and pressure have made these rocks change.

Metamorphic Rock – ‘changing rock’ Marble Slate Quartzite

ROCK TYPES Basalt Limestone Marble Granite Sandstone Slate Rhyolite Igneous rocks Sedimentary rocks Metamorphic rocks Basalt Limestone Marble Granite Sandstone Slate Rhyolite Coal Gneiss Gabbro Mudstone Schist