Chapter 4

The Rock Cycle Make sure your rock cycle is drawn!!

The Rock Cycle Processes that shape the earth – Weathering- water, wind, ice, and heat break down rock – Erosion- process where water, wind, ice or gravity transports soil and sediment from one location to another – Deposition- process which material is at rest – Uplift- process where movement in the earth causes rocks from the inside of earth to move

The Rock Cycle Pg 92-93

The Rock Cycle Various paths to the rock cycle- pg 94 The rock cycle can vary and change in different ways. Three rock types – Sedimentary – Igneous – Metamorphic

Rock Cycle After rock is classified into one of the 3 rock types it can be classified further -Composition- chemical makeup of a rock -Texture- size, shape, or position of a rock’s grains

Igneous Rock Igneous rock begins as magma Magma can form by – When rock is heated – When pressure is released – When rock changes compositions

Igneous Rock Composition and texture of igneous rock – Light colored rocks-less dense, rich in aluminum, potassium, silicon, and sodium called felsic rocks – Dark colored rocks- mafic rocks, rich in calcium, iron, and magnesium – Texture determined by how fast magma cools

Igneous Rock Igneous Rock Formations – Intrusive igneous rock: course grained texture, cools slowly, pushes into rock below – Extrusive igneous rock: forms from magma that erupts, cools rapidly

Sedimentary Rock Sedimentary rock forms near the surface of earth Materials that have been weathered form a natural cement that bonds rock and mineral fragments together Strata- most noticeable feature- layers

Sedimentary Rock Composition of Sedimentary rock- classified by way it is formed – Clastic- fragments of minerals together – Chemical- forms from solutions of dissolved minerals and water – Organic- formed from fossils (limestone or coral) coal is also organic

Sedimentary Rock Sedimentary rock structures – Most important feature of sedimentary rock- stratification- rocks in layers – Sed. Rocks sometimes record motion of wind on lakes, oceans, rivers, and sand dunes in features called ripple marks – Mud cracks form when find grained sediments at the bottom of water are exposed to the air and dry out.

Metamorphic Rock Rocks in which the structure, texture, or composition have been changed. Contact metamorphism- heated with nearby magma, occurs near igneous intrusions Regional metamorphism- pressure builds up in a rock that is deep below the surface, occurs a distance away from earth’s surface

Metamorphic Rock Composition: occurs when temperature or pressure inside the earth’s crust change Texture: – Foliated- mineral grains arranged in planes or bands – Nonfoliated- mineral grains not arranged in planes or bands

Metamorphic Rock Deformation- change in the shape of a rock caused by a force placed on it. Folds or bends indicate a rock has been deformed.