Presentation on theme: "Rocks and the Rock Cycle P.86"— Presentation transcript:
1 Rocks and the Rock Cycle P.86 Standard IIIA: Earth Structure and ProcessesThe student will identify Earth’s composition, structure and processes.The student will classify and identify rocks and minerals using characteristics including but not limited to density, hardness and streak.The student will describe the various processes and interactions of the rock cycle.
2 Learning Objectives – Rocks & the Rock Cycle P. 86 Describe the rock cycle and each of its processes.Describe the three types of rocks, how they formed and how they are classified and identified.Be able to identify rocks as either Igneous, Metamorphic or Sedimentary.
3 There is a hierarchy to the elements of Geology Atoms make up elements.There is a hierarchy to the elements of GeologyElements combine to form the natural compounds.Natural compounds and elements combine to form minerals..Minerals make up rocks.Here the intent is to show how the various pieces; atoms, elements, compounds, and minerals, rocks and even the Earth, are related to each other in a hierarchy.Classroom exercise- Take some road salt (larger pieces of rock salt used to melt ice and snow) and have the students look at them and describe what they see. A magnifying glass is very handy here. Students should note blocky nature made up of various sizes of blocks or cubes. As appropriate, note the differences between 2 dimensional references like square or circle and 3 dimensional references like block, cube and sphere.This will require three samples of rock salt that will be broken to show the physical characteristics of a mineral. With goggles on to protect the eyes, have a student gently tap sample 1 with a metal spoon (or some other relatively heavy blunt object) and observe what happens (salt/halite cleaves or breaks into many smaller blocks or cubes). On a sample 2 use a butter knife placed diagonally on one of the faces of a salt block and gently tap edge of the knife blade. What happens? (results is similar to the spoon maybe fewer small pieces) On sample 3 use a butter knife placed parallel to the sides about in the middle of a piece of salt and gently tap edge of the knife blade. What happens? (Fewer, cleaner breaks / fewer pieces because energy was direct more specifically along the cleavage planes in the rock salt. - much like a diamond cutter does when the start working on a new diamond).How many crystal faces are there on a cube - how many directions of cleavage are there What is the angular relationships. Examine regular table salt with a hand lens and describe what you see. Grow crystals from salt water or sugar water - have students dissolve the sugar or salt in water - how can they tell when they have added ‘enough?’ When the salt or sugar does not dissolve any more but goes right to the bottom of the glass - what happens with mixture is heat? (supersaturated solution). Try a mixture of salt and sugar to see what happens. What other household materials could be used to grow crystals (alum, Epson salts …). Students should observer the crystal growing experiment daily and record their observations. Have students explain how the terms dissolve, mixture, precipitate and crystal relate to the crystal growing exercise. Another variation is to have students place their crystal growing containers in different locations – sunny window sill, on heat register, in a storage closet and have them discuss what effect the location had on the outcome of their experiment.For even more go to GEOMAN’sCreated October 2, 2000, revised September 2001Rocks make up the Earth.
4 Rocks and the Rock Cycle Chapter 4 a mixture of one or more minerals, mineraloids, volcanic glass and/or organic (living) matter
5 Rocks and the Rock Cycle Chapter 4 Shows the processes by which Earth materials change to form the 3 different types of rocks.
9 Rocks and the Rock Cycle Chapter 4 Page. 87 There are three main types of rocks:1. Igneous – rocks formed from magma or lavaClassified based onWhere they formed(Intrusive or Extrusive)Chemical composition.(Basaltic or Andesitic or Granitic)2. Metamorphic – rocks changed from heat and pressureClassified based on their texture.(Foliated or Non-foliated)3. Sedimentary – rocks formed from compacted sedimentsClassified based on the composition & origin of the sediments.(Detrital or Chemical or Organic)
10 Igneous Rocks P. 90 Rhyolite IGNEOUS ROCKS are rocks that formed from the cooling and crystallization of magma or lava.Igneous rocks are classified two ways;by where they were formed (Intrusive or Extrusive)by their chemical composition. (Basaltic or Andesitic or Granitic)1. Extrusive igneous rocks (aka Volcanic rocks) form at the earth's surface as lava cools - forming small crystals (can’t see with naked eye).These rocks have a fine (small) crystalline texture.ExamplesBasaltRhyoliteScoria (no crystals)Pumice (no crystals)Obsidian (no crystals)Rhyolite
11 Igneous Rocks2. Intrusive igneous rocks (aka Plutonic Rocks) form deep underground where magma cools slowly allowing big crystals to form that are easily seen.These rocks have a coarse (large) crystalline texture.Examples:GraniteGabbro
12 Igneous RocksIgneous rocks are also classified by their chemical composition.Basaltic (aka Mafic) Igneous rocks are composed of mostly Iron (Fe) and Magnesium (Mg).Examples: Basalt, GabbroAndesitic Igneous rocks (aka Intermediate chemical composition). In between granitic and basaltic).Examples: Andesite, DioriteGranitic (aka Felsic) Igneous rocks are composed mostly of Silicon (Si), Oxygen (O) and Aluminum (Al).Examples: Granite, Rhyolite
13 Igneous Rocks P. 93 Basaltic Composition Intermediate Composition GraniticComposition
14 Metamorphic Rocks P. 97Metamorphic rocks are rocks that have been changed in form due to heat, pressure, and chemical alteration. They are subdivided into two types.1. FOLIATED – The mineral grains flatten and line up in parallel bands or layers.Examples of foliated Metamorphic RocksSlateSchistGneiss2. NONFOLIATED - Mineral grains change, grow and rearrange but don’t form bands.Examples of non-foliated Metamorphic RocksMarbleQuartzite
15 Metamorphic Rocks P. 97 Metamorphic Rocks DO NOT MELT! Minerals can grow larger in size.Elements can rearrange and bond with different elements in the rock to form new minerals.Greenstone on your deskThere are Levels of MetamorphismSlate (less h&p)-Phyllite-Schist-Gneiss (more h&p)
16 Metamorphic Rocks P. 97Examples of rocks changing into met. Rocks due to heat and pressure.Shale (sed) changes to slateBasalt (Ig) changes to schistBasalt (Ig) can also change to greenstoneSandstone (sed) changes into QuartziteSlate (met) changes into phyllite (met) then schist (met) then gneiss (met)Granite (Ig) changes into granite gneiss
17 Sedimentary Rocks P. 101Sediments are broken pieces of rocks and minerals.Clay, silt, sand, gravel, cobble, boulder are sizes of sedimentsWeathering is the process of breaking rocks into smaller pieces by wind, water, glaciers and gravity.Erosion and deposition is the process of MOVING (transporting) these materials.Sedimentary Rocks form when sediments are compacted (squeezed) and cemented (glued) together.Sedimentary rocks can also be formed by evaporation or precipitation from solution.Most sedimentary rocks are formed of layers of materials that have washed into lakes, rivers, and the ocean.
18 Sedimentary Rocks P. 101 There are 3 groups of Sedimentary Rocks 1. Clastic (detrital) Sedimentary Rocks form from bits and pieces of other rocks.2. Chemical Sedimentary Rocks consist of minerals deposited from a solution.3. Organic Sedimentary Rocks consist of organic matter such as plants and animal remains.
19 1. Detrital (Clastic) Sedimentary Rocks Rocks formed from the compaction and cementation of sediments.Weathering and erosion by gravity, rivers, ice/glaciers, wind, and waves carry sediment.ExamplesConglomerateSandstoneShale
21 2. Chemical Sedimentary Rocks Chemically-formed sedimentary rocks come from minerals carried in solution into lakes and seas.The minerals that form the rock precipitate out or are left when the solution evaporates.ExamplesLimestone (calcium carbonate)Gypsum (calcium sulfate)Salt (sodium chloride)
23 3. Organic Sedimentary Rocks Organically-formed sedimentary rocks form from the remains of plants and animals.ExamplesFossil limestoneCoalCoquinaChalkWhy can’t igneous or metamorphic rocks have fossils?
24 Rocks and the Rock Cycle - Chapter 4 PowerPoint Presentation You and your group will create a PowerPoint Presentation on three types of rock and the rock cycle.Each member is responsible for completing the research for the presentation using his/her textbook. Use the handout provided and complete the outline. Each member completes a section of the outline. All members then review the information and check for accuracy.All members work together in putting the information into the slide show. *You cannot begin the show until your research is completed.Diagrams, examples and pictures of rocks can be added by using the links on our web site.Copy, Paste any pictures you use – do NOT save them on the computer!Save all work into your group’s folder.
25 Rocks and the Rock Cycle - Chapter 4 PowerPoint Presentation Rubric for Scoring: Possible EarnedTitle Slide with names and group picture 3 pts. _____Metamorphic rock is formed when 3 pts. _____Types of metamorphic rock and definitions 4 pts. _____Examples: picture and name (2) 4 pts. _____Igneous rock is formed when 3 pts. _____Types of igneous rock and definitions 4 pts. _____Sedimentary rock is formed when 3 pts. _____Types of sedimentary rock and definitions 6 pts. _____Examples: picture and name (3) 6 pts. _____The Rock Cycle explanation 6 pts. _____Rock Cycle Diagram 4 pts. _____Questions/Presentation 5 pts. _____Total pts. _____