Rocks and the Rock Cycle

Three Types of Rocks Rocks are classified by how they form –Igneous –Sedimentary –Metamorphic –Rocks can change from one type to another over time Schist

Rock Classification Rocks are classified by : –How they form –Texture –Grain size –Mineral composition Conglomerate Sedimentary Rock

Igneous Rocks Igneous rock: forms when molten rock (magma) cools and hardens Classified by: –Where they form –Crystal (grain) size Basalt

Intrusive Igneous Rock Intrusive igneous: cooling takes place slowly beneath Earth’s surface granite

Extrusive Igneous Rock Extrusive igneous: cooling takes place rapidly on Earth’s surface Pumice

Sedimentary Rock Sedimentary rock: forms from the compaction and/or cementation of sediments This process is called lithification Sediments are: –Rock pieces –Mineral grains –Shell fragments Limestone

How do sediments form? Sediments form through the processes of weathering and erosion of rocks exposed at Earth’s surface weathering erosion

Sedimentary Rock con’t…. Sedimentary rock can also form from the chemical depositing of materials that were once dissolved in water When water evaporates, minerals are left behind and form rock gypsum

Metamorphic Rock Metamorphic rock: forms when any rock type is changed into a different kind of rock Changes due to great heat and/or pressure Gneiss

How does rock change? Rocks are heated, squeezed, folded, or chemically changed by contact with hot fluids marble

The Rock Cycle

The Earth Recycles Rock The rock cycle is an ongoing series of processes inside Earth and on the surface Slowly changes rocks from one kind to another Any type of rock can change into another type

How does this relate to plate tectonics? Plate movement drives the rock cycle –Subduction (1 plate pushed under another plate) Re-melts rock into magma –Mountain building Folding, faulting, uplift Exposes rock at the surface to be weathered and eroded

a.Cementation and compaction (lithification) b.Heat and pressure c.Weathering, transportation(erosion), and deposition d.Cooling and solidification e.Melting

Rocks/Rock Cycle Foldable Your foldable should include the following: 1.Name of each rock type 2.How each rock type formed 3.A brief description of rock type 4.At least 2 examples of each rock type 5.Illustrate 1 example for each rock type

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Do Now – Tuesday March 11 In Textbook: Complete pg. 107 #1-8

Do Now – Thursday March 4 RockTextureCompositionComments Conglomer ate Coarse, 2mm Rounded pebbles Rounded pebbles, sand and clay can easily be seen SandstoneMedium,.0625 – 2 mm Quartz, other minerals and rock fragments Sand grains can be seen; rough surfaces ShaleMicroscopic, mm Clays, micasHas muddy appearance LimestoneCoarse to fineCalcite, shellsMay contain fossils, seashells; fizzes when in hydrochloric acid ChertFineQuartzIs light-colored; also called flint; once used for arrowheads Rock saltCoarse to fineHaliteHas salty taste; table salt Limestone is composed of the mineral A. quartz B. calcite C. halite D. gypsum Based on the information given about each of these rocks, into which rock type would all these examples be classified? A. Igneous B. Metamorphic C. Sedimentary D. Mineral

Gypsum Moh's Hardness Scale Approximate Hardness of Common Objects Talc Gypsum 1 2 Fingernail (2.5) Calcite 3 Copper penny (3.5) Fluorite 4 Iron nail (4.5) Apatite 5 Glass (5.5) Feldspar 6 Steel file (6.5) Quartz Topaz 7 Streak plate (7.0) Topaz 8 Corundum 9 Diamond 10 Which statement is best supported by the data shown? A.An iron nail contains fluorite. B. A streak plate is composed quartz. C. Topaz is harder than a steel file. D. Apatite is softer than a copper penny.

Based on the processes shown in the diagram, which type of rock is formed at #1? A. Sedimentary B. Igneous C. Metamorphic D. Clastic Because heat and pressure are needed to form #3, it must be what type of rock? A. Sedimentary B. Igneous C. Metamorphic D. Clastic