2 Why Are Rocks Important To Us? BuildingsRoadsBridgesConcreteExtract minerals – like iron (Fe) to make steelToothpasteSaltSandpaperDecorationsJewelry
3 1. Why is it important to have a basic understanding of the rock cycle? Rocks contain clues about the environment. Helps us understand the formation of the earth.
4 2. RockAny solid mass of minerals or mineral-like matter
5 3. Do most rocks occur as one mineral or as a mixture of minerals?
6 4. Some rocks are made of non-mineral material, can you name one? Coal
7 Coal - begins as layers of plant matter accumulate at the bottom of a body of water. For the process to continue the plant matter must be protected from biodegradation and oxidization, usually by mud or acidic water. This trapped atmospheric carbon in the ground in immense peat bogs that eventually were covered over and deeply buried by sediments under which they metamorphosed into coal. Over time, the chemical and physical properties of the plant remains (believed to mainly have been fern-like species antedating more modern plant and tree species) were changed by geological action to create a solid material.Coal, a fossil fuel, is the largest source of energy for the generation of electricity worldwide.
12 The Rock CycleThe Rock Cycle is a group of changes, this change does not necessarily have to be a chemical change.Igneous rock can change into sedimentary rock or into metamorphic rock.Sedimentary rock can change into metamorphic rock or into igneous rock.Metamorphic rock can change into igneous or sedimentary rock.Almost all of rock today that we have on earth is made up of all the same stuff as the rocks that dinosaurs and other ancient life forms walked, crawled, or swam overWhile the stuff that rocks are made of has stayed the same, the rocks themselves, have notOver time rocks are recycled into other rocksMoving tectonic plates are responsible for destroying and forming many types of rocks
13 6. List the 3 types of rocksIgneousMetamorphicSedimentary
14 7. Igneous RocksIgneous rock forms when magma cools and makes crystals.Magma is a hot liquid made of melted minerals. When magma pours onto the earth’s surface it is called lava. The minerals can form crystals when they cool.Igneous rock can form underground, where the magma cools slowly. Or, igneous rock can form above ground, where the magma cools quickly.The crystals grow together and form one igneous rocks.
15 8. What kind of igneous rocks form when molten lava cools and hardens? ExtrusiveExtrusive = forced out while molten through cracks in the earth's surface
16 9. What is the Latin word that the word igneous comes from and what does it mean? ignis = fire
17 10. Intrusive Igneous Rocks Form from magma below the earth’s surface
18 11. Extrusive Igneous Rocks Formed by lava on the Earth’s surface
19 12. What is the difference between magma and lava? Lava = molten rock flowing on the earth’s surfaceMagma = molten rock below the earth’s surface
20 Silicon, oxygen, aluminum, iron, calcium, sodium, potassium, magnesium 13. What are the 8 elements that make up magma?Silicon, oxygen, aluminum, iron, calcium, sodium, potassium, magnesium
21 14. In what ways are the two rocks similar? Look at the granite rock (A on age 71) and the rhyolite rock (B on page 71)GraniteRhyolite14. In what ways are the two rocks similar?Both are from melted rockTheir composition is the same
22 15. In what ways are the two rocks different? GraniteRhyoliteGranite – coarse texture, made from magmaRhyolite – fine texture, made from lava
23 16. What causes the two rocks to be different? GraniteRhyoliteGranite – Slow cooling below the earth’s surfaceRhyolite – Quick cooling on the earth’s surface
24 17. Why do you think some rocks are heavier than others? Some are denser – less air space between particles
25 Which rock would have greater density? PumiceGranite
26 Classifying RocksRocks can be classified, or put into groups with similar characteristics, by looking at the rocks texture, mineral composition, and color.
27 18. What is texture? The size, shape, and pattern of the rock’s grain Glassy(nice)
28 19. Composition (what’s it made of?) The minerals that make up the different parts of a rockExamples: Quartz Feldspar Magnesium Iron
29 ADDRock ColorThe apparent color of the rock, on the inside and the outside
30 20. Slow cooling magma will form rocks with a a. coarse grained texture.b. fine grained texture.c. glassy texture.d. porphyritic texture.
31 Rapid cooling magma will form rocks with a a. coarse grained texture.b. fine grained texture.c. glassy texture.d. porphyritic texture.
32 22. When lava spews onto the earth’s surface rocks will form with a a. coarse grained texture.b. fine grained texture.c. glassy texture.d. porphyritic texture.
33 23. Magma that is located deep within the earth may take tens of thousands of years to harden. The rocks that form in this case will have aa. coarse grained texture.b. fine grained texture.c. glassy texture.d. porphyritic texture.
34 24. Which 2 minerals are granitic rocks composed of? QuartzFeldspar
35 25. Which 2 minerals are basaltic rocks composed of? MagnesiumIron
36 Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks.How do sedimentary and igneous rocks change?The rocks are under tons and tons of pressure, which fosters heat build up, and this causes them to change.If you exam metamorphic rock samples closely, you'll discover how flattened some of the grains in the rock are.
37 The Rock DivisionsRock divisions occur in three major families based on how they formed: igneous, sedimentary, and metamorphic.Each group contains a collection of rock types that differ from each other on the basis of the size, shape, and arrangement of mineral grains.Just remember 3 types of rocks=3 divisions. (igneous, sedimentary, and metamorphic)
38 Texture: the size, shape, and pattern of the rock’s grain. Classifying RocksWhen classifying a rock sample geologists observe the rock’s color and texture and determine its mineral composition.Texture: the size, shape, and pattern of the rock’s grain.Color: the apparent color of the rock, on the inside and the outside.Mineral composition: The minerals that make up the different parts of a rock.
39 Texture: Grain SizeOften, the grains in a rock are large and easy to see.Such rocks are said to be coarse-grained. In other rocks, the grains are so small that they can only be seen with a microscope.These rocks are said to be fine-grained.Notice the difference in texture between the fine-grained slate and the coarse-grained diorite to the right.
40 Texture: Grain Shape The grains in a rock vary widely in shape Some grains look like tiny particles of fine sandOthers look like small seeds or exploding starsIn some rocks, such as granite, the grain results from the shapes of the crystals that form the rockIn other rocks, the grain shape results from fragments of other rockThese fragments can be smooth and rounded, like the fragments in conglomerate, or they can be jagged, like the fragments in brecciaYou can compare conglomerate and breccia one the next slide
41 Texture : Grain Pattern The grains in a rock often form patterns. Some grains lie in flat layers that look like a stack of pancakes.Other grains form wavy, swirling patterns. Some rocks have grains that look like rows of multicolored beads, as in the sample of gneiss shown above.Other rocks, in contrast, have grains that occur randomly throughout the rock.
42 Different Types of Texture Fine-Grained, Coarse-Grained, Rounded Grain, Jagged Grain, Nonbanded, Banded
43 2 Types of Igneous RocksINTRUSIVE IGNEOUS ROCKS – When igneous rocks are formed by magma that cools BENEATH Earth’s surface, they are called intrusive igneous rocksEXTUSIVE IGNEOUS ROCKS – When igneous rocks are formed by LAVA ON Earth’s surface, they are called extrusive igneous rocks
44 Lithification The process by which sediment becomes sedimentary rock 1st step : erosion2nd step : deposition3rd step : compaction4th step : cementation
45 Sedimentary Rocks : Erosion Destructive forces are constantly breaking up and wearing away all the rocks on Earth’s surfaceThe forces include heat and cold, rain, waves, and grinding iceErosion occurs when running water or wind loosens and carry away the fragments of rock.
46 Sedimentary Rocks: Deposition Eventually, the moving water or wind slows and deposits the sediment.If water is carrying the sediment, rock fragments and other materials sink to the bottom of a lake or ocean.Deposition is the process by which sediment settles out of the water or wind carrying it.After sediment has been deposited, the processes of compaction and cementation change the sediment into sedimentary rock.In addition to particles of rock, sediment may include shells, bones, leaves, stems, and other remains of living things.Over time, any remains of living things in the sediment may slowly harden and change into fossils trapped in the rock.
47 Sedimentary Rocks: Compaction At first the sediments fit together loosely. But gradually, over millions of years, thick layers of sediment build up.These layers are heavy and press down on the layers beneath them.Then compaction occurs.Compaction is the process that presses sediments together.Year after year more sediment falls on top, creating new layers.The weight of the layers further compacts the sediments, squeezing them tightly together.The layers often remain visible in the sedimentary rock.
48 Sedimentary Rocks: Cementation While compaction is taking place, the minerals in the rock slowly dissolve in the water.The dissolved minerals seep into the spaces between particles of sediment.Cementation is the process in which dissolved minerals crystallize and glue particles of sediment together.It often takes millions of years for compaction and cementation to transform loose sediments into solid sedimentary rock.
49 Sedimentary Transformations Point A: water or wind deposits sedimentsPoint B: The heavy sediments press down on the layers beneathPoint C: Dissolved minerals flow between the particles and cement them together
50 Metamorphic Rock Pictures Granite, Gneiss, Shale, Slate, Sandstone, and Quartzite are good examples of metamorphic rocks.
51 Bet Cha’ Weren’t Expecting A…. POP QUIZ!!!!!* What are the three types of rock?Which type of rock has been formed by magma or lava?What do we classify rocks by?How do sedimentary rocks form (in order)?Metamorphic rocks are rocks that have?(fill in the blank)What is the process of sediments forming a sedimentary rock?What does “ignis” mean in the word igneous?*Answers are on next slide!
52 ANSWERS!!!! Igneous, Sedimentary, and Metamorphic Igneous Texture, Color, and Mineral CompositionErosion, Deposition, Compaction, CementationMorphedLithification“ignis” means fire
53 Bibliography www.dlese.com Earth Science Textbook Google Images ( I KNOW THIS DOESN’T COUNT IM JUST TELLING YOU!!)
54 Sedimentary RocksSedimentary rocks form from particles deposited by water and windIf you have ever walked along a beach (which I am sure you have) you may have noticed tiny sand grains, mud, and pebbles.These are some sediments that eventually form into sedimentary rocksSedimentary Rocks can form in 4 ways by:ErosionDepositionCompactionCementation