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What is a Rock? Naturally-occurring mixtures of minerals, mineraloids (no crystals), or organic matter. Naturally-occurring mixtures of minerals, mineraloids.

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Presentation on theme: "What is a Rock? Naturally-occurring mixtures of minerals, mineraloids (no crystals), or organic matter. Naturally-occurring mixtures of minerals, mineraloids."— Presentation transcript:

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2 What is a Rock? Naturally-occurring mixtures of minerals, mineraloids (no crystals), or organic matter. Naturally-occurring mixtures of minerals, mineraloids (no crystals), or organic matter.

3 Types of Rocks… The three main kinds of rock are igneous, sedimentary and metamorphic rock. The three main kinds of rock are igneous, sedimentary and metamorphic rock. –Igneous rock: forms when magma/lava cools and hardens –Sedimentary rock: forms when sediments are buried, compacted & cemented together –Metamorphic rock: forms when existing rock is subjected to great heat & pressure over a long period of time

4 What is the difference between a rock and a mineral? Rocks are made up of ONE or MORE minerals. Rocks are made up of ONE or MORE minerals.

5 Once a rock is formed, does it stay the same rock forever? NO! NO!

6 Rocks are continually changed by many processes, such as weathering, erosion, compaction, cementation, melting, and cooling Rocks are continually changed by many processes, such as weathering, erosion, compaction, cementation, melting, and cooling Rocks can change to and from the three types Rocks can change to and from the three types

7 What is the process through which rocks change? The Rock Cycleearth materials change back and forth among the different types of rocks The Rock Cycleearth materials change back and forth among the different types of rocks

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10 No set path a rock takes to become another kind of rock No set path a rock takes to become another kind of rock

11 IGNEOUS SEDIMENTARY METAMORPHIC Weathering, Erosion, Compaction, Cementation Recrystallization Weathering, Erosion, Compaction, Cementation Recrystallization Melting, Solidification

12 How are rocks redistributed? The core, mantle, & crust are one giant rock recycling machine The core, mantle, & crust are one giant rock recycling machine

13 Ignis = Latin for fire Ignis = Latin for fire Formed from the cooling of either magma or lava Formed from the cooling of either magma or lava The most abundant type of rock The most abundant type of rock Classified according to their origin and composition Classified according to their origin and composition Igneous Rocks come from magma/lava cooling down. Igneous Rocks come from magma/lava cooling down.

14 ORIGIN Where rocks are formed Below ground = from magma (intrusive igneous rock) Below ground = from magma (intrusive igneous rock) Usually have LARGE crystal grains (they cooled slowly) Cooling could have taken hundreds of years. Usually have LARGE crystal grains (they cooled slowly) Cooling could have taken hundreds of years.

15 Some have large & small crystals (called porphyritic)

16 Above ground = from lava (extrusive igneous rock) Above ground = from lava (extrusive igneous rock) Usually have SMALL or NO crystals (they cooled too quickly) Usually have SMALL or NO crystals (they cooled too quickly)

17 Granite: Intrusive or Extrusive? Why?

18 Obsidian: Intrusive or Extrusive? Why?

19 COMPOSITION What kind of substances or minerals are rocks made of

20 Basaltic Igneous Rocks made from lava/magma that is low in silica, rich in iron and magnesium. Rocks are dark- colored.

21 Granitic Igneous Rocksmade from magma/lava high in silica and oxygen. Rocks are light- colored.

22 Andesitic Igneous Rocks have a composition between basaltic and granitic.

23 Diorite-has course grains

24 Basalt-no course grains

25 Granite

26 Formed from sediments (rock fragments, mineral grains, animal & plant remains-shells, bones, leaves, stems) that are pressed or cemented together or when sediments precipitate out of a solution. Formed from sediments (rock fragments, mineral grains, animal & plant remains-shells, bones, leaves, stems) that are pressed or cemented together or when sediments precipitate out of a solution.

27 These sediments are moved by wind, water, ice or gravity then deposited into layers. These sediments are moved by wind, water, ice or gravity then deposited into layers. Sedimentary rocks represent 7% of the Earths crust, but they cover 70% of the Earths surface. Sedimentary rocks represent 7% of the Earths crust, but they cover 70% of the Earths surface. Sedimentary rocks are fossil-carrying rocks. Sedimentary rocks are fossil-carrying rocks.

28 What turns sediments into solid rock? Water or wind breaks down and deposits sediment (erosion & deposition) Water or wind breaks down and deposits sediment (erosion & deposition) Elements of Erosion are heat, cold, rain, waves, and grinding ice. Elements of Erosion are heat, cold, rain, waves, and grinding ice.

29 At first sediments fit together loosely, over long periods of time, thick layers build up. Because of the heavy layers, the upper layers press down on the layers below them, causing Compaction. At first sediments fit together loosely, over long periods of time, thick layers build up. Because of the heavy layers, the upper layers press down on the layers below them, causing Compaction.

30 Dissolved minerals flow between the particles and cement them together (cementation) Dissolved minerals flow between the particles and cement them together (cementation)

31 How can sedimentary layers help us understand the age of fossils? As sedimentary rocks are deposited, they form horizontal layers As sedimentary rocks are deposited, they form horizontal layers Scientists know that the layers on top (and the fossils in the top layer) are YOUNGER than the fossils in lower layers. Scientists know that the layers on top (and the fossils in the top layer) are YOUNGER than the fossils in lower layers.

32 3 Types of Sedimentary Rocks: Clastic (also called Detrial)made of broken pieces of other rocks. Formed when rock fragments are squeezed together. Clastic (also called Detrial)made of broken pieces of other rocks. Formed when rock fragments are squeezed together.

33 Clastic-Sedimentary Rocks Shale: Formed from tiny particles of clay compacted together. Shale: Formed from tiny particles of clay compacted together. Sandstone: Forms from the compaction and cementation of small particles of sand. Sandstone: Forms from the compaction and cementation of small particles of sand.

34 Clastic-Sedimentary Rocks Conglomerate: Formed from fragments of various sizes of rocks and pebbles. Fragments are rounded because they have been worn along riverbeds. Conglomerate: Formed from fragments of various sizes of rocks and pebbles. Fragments are rounded because they have been worn along riverbeds. Breccia: Fragments are jagged with sharp edges. Formed from various size of rocks and pebbles. Breccia: Fragments are jagged with sharp edges. Formed from various size of rocks and pebbles.

35 Organicremains of plants and animals are deposited in thick layers Organic refers to substances that once were part of living things or were made by living things which contain calcite or calcium carbonate. (Can be tested by using acid) Organic refers to substances that once were part of living things or were made by living things which contain calcite or calcium carbonate. (Can be tested by using acid) 3 Types of Sedimentary Rocks:

36 Organic-Sedimentary Rocks Coal: Remains of swamp plants buried in water or by volcanic ash. Coal: Remains of swamp plants buried in water or by volcanic ash. Limestone: Formed by hard shells of once living things such as coral, clams, oysters, and snails. When they die their shells pile up and are covered by other sediments compacting and cementing them. Limestone: Formed by hard shells of once living things such as coral, clams, oysters, and snails. When they die their shells pile up and are covered by other sediments compacting and cementing them.

37 Types of Limestone Chalk-can be naturally occurring and in rock form. Chalk-can be naturally occurring and in rock form. Coquina-made of large fragments of shells. Coquina-made of large fragments of shells.

38 Chemicalminerals dissolved in lakes, seas, or underground water. Can occur when lakes evaporate. Chemicalminerals dissolved in lakes, seas, or underground water. Can occur when lakes evaporate. 3 Types of Sedimentary Rocks:

39 Chemical-Sedimentary Rocks Rock Salt: Made of the mineral halite. Rock Salt: Made of the mineral halite. Gypsum: Formed by evaporation in dry climates. Gypsum: Formed by evaporation in dry climates.

40 Rocks that have changed due to intense temperature and pressure Rocks that have changed due to intense temperature and pressure Meta means change and morphosis means form in Greek Meta means change and morphosis means form in Greek Igneous, sedimentary and other metamorphic rocks can change to become metamorphic rocks Igneous, sedimentary and other metamorphic rocks can change to become metamorphic rocks

41 What occurs in the Earth to change these rocks? Pressure from overlying rock layers Pressure from overlying rock layers High heat, but not enough to melt the rock High heat, but not enough to melt the rock Rocks may be flattened or bent or atoms may be exchanged to form new minerals. Rocks may be flattened or bent or atoms may be exchanged to form new minerals.

42 *You can think of metamorphic rocks as a squished peanut butter & jelly sandwich in your lunch. *You can think of metamorphic rocks as a squished peanut butter & jelly sandwich in your lunch.

43 Where do metamorphic rocks usually form? Where magma intrudes relatively cool rock Where magma intrudes relatively cool rock Near colliding plates (near mountain ranges) Near colliding plates (near mountain ranges) Places that are covered miles thick with other rock causing pressure Places that are covered miles thick with other rock causing pressure When hot water intrudes rock When hot water intrudes rock Where a meteorite strikes Earth (rare) Where a meteorite strikes Earth (rare) Where lightning bolts strike rocks (rare) Where lightning bolts strike rocks (rare)

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45 How are metamorphic rocks classified? Look at Pages 162-163 in your books Foliatedmineral grains are flattened and line up in parallel bands Foliatedmineral grains are flattened and line up in parallel bands Example: gneiss formed from rearrangement of minerals in granite into bands Example: gneiss formed from rearrangement of minerals in granite into bands

46 How are metamorphic rocks classified? Non-FoliatedNo bands are formed Non-FoliatedNo bands are formed Example: marble formed from limestone Example: marble formed from limestone

47 Rocks Transformed Limestone Marble ShaleSlate

48 Rocks Transformed Sandstone Quartzite MudstoneSchist Gneiss or

49 Say you have an unknown rock how do you classify it? Color: Like with minerals, color alone does not provide enough information to identify a rock. Color: Like with minerals, color alone does not provide enough information to identify a rock.

50 Say you have an unknown rock how do you classify it? Texture can be very useful. Look at and feel the rocks surface. Texture can be very useful. Look at and feel the rocks surface. Some are smooth and glassy others are rough and chalky. Some are smooth and glassy others are rough and chalky. Grain Size: Large or Small Grain Size: Large or Small Grain Shape: Fine Grained or Jagged Grain Shape: Fine Grained or Jagged Grain Patterns: Flat Layers, Wavy, banded, or random. Grain Patterns: Flat Layers, Wavy, banded, or random. No Visible Grain: Some cool to fast to have grains. No Visible Grain: Some cool to fast to have grains.

51 Say you have an unknown rock how do you classify it? Mineral composition: By looking under a microscope, a geologist can identify the minerals it contains. Mineral composition: By looking under a microscope, a geologist can identify the minerals it contains. You can use acid to check for carbonates. (Limestone or Chalk) You can use acid to check for carbonates. (Limestone or Chalk)

52 Say you have an unknown rock how do you classify it? Origin: Where it came from! Origin: Where it came from! Metamorphic: Usually have bigger crystals because of increased heat and pressure. Metamorphic: Usually have bigger crystals because of increased heat and pressure. Igneous: Usually is made up of very large particles. Igneous: Usually is made up of very large particles. Sedimentary: Small solid pieces of material that come from rocks or living things. (Smoother) Sedimentary: Small solid pieces of material that come from rocks or living things. (Smoother)

53 Rock Cycle Animations Rock Cycle Quiz Rock Cycle Quiz Rock Cycle Quiz Rock Cycle Quiz Rock Cycle Animation #1 Rock Cycle Animation #1 Rock Cycle Animation #1 Rock Cycle Animation #1 Weathering and Erosion Quiz Weathering and Erosion Quiz Weathering and Erosion Quiz Weathering and Erosion Quiz Rock Cycle Video (Made by a Middle School Student) Rock Cycle Video (Made by a Middle School Student) Rock Cycle Video (Made by a Middle School Student) Rock Cycle Video (Made by a Middle School Student) Go to the next slide to play Jeopardy. Go to the next slide to play Jeopardy.

54 Jeopardy Game The Rock Cycle

55 The Rock Cycle Igneous Rocks 10 pts 20 pts 30 pts 40 pts 10 pts 20 pts 30 pts 40 pts Metamorphic Rocks 10 pts 20 pts 30 pts 40 pts Sedimentary Rocks 10 pts 20 pts 30 pts 40 pts 50 pts

56 Question 1 Mixture of minerals, volcanic glass, organic matter, or other material Rock Check Answer

57 Question 2 A model showing the processes that create and change rock. Rock Cycle Check Answer

58 Question 3 _________ rock can be changed by heat and pressure into metamorphic rock. Sedimentary Rock Check Answer

59 Question 4 __________ rock can be broken into fragments that may later form sedimentary rock. Igneous Check Answer

60 Question 5 ______ rock can melt and cool to form igneous rock. Metamorphic Check Answer

61 Question 6 Magma reaches the surface flows from a volcano as ____________. Lava Check Answer

62 Question 7 Magma trapped below the surface forms large – grained ______________ rock when it cools. Intrusive Check Answer

63 Question 8 Magma cooling at or near Earths surface forms small-grained __________ igneous rock. Extrusive Check Answer

64 Question 9 Igneous rocks are classified in 2 ways. 1.______________ 2.______________ Intrusive and extrusive Check Answer

65 Question 10 Volcanic glass rock __________ so quickly that few crystals form. cool Check Answer

66 Question 11 _____________ and ______________ result from one layer of rock on top of another layer. Heat and pressure Check Answer

67 Question 12 Sometime temperature and pressure are great enough to melt rock, forming ______________. magma Check Answer

68 Question 13 _____________ texture – mineral grains flatten and line up in parallel layers or bands. Foliated texture Check Answer

69 Question 14 _______ texture - mineral grains grow and rearrange but do not form layers. Nonfoliated texture Check Answer

70 Question 15 Sometimes ____________ flattens mineral grains in rocks without melting them. Pressure Check Answer

71 Question 16 Type of rock mostly found on the exposed surface of Earth. Sedimentary Rock Check Answer

72 Question 17 Sedimentary Rocks form in __________. layers Check Answer

73 Question 18 Rock fragments, mineral grains, and bits of plants and animal remains moved by wind, water, ice or gravity are called _________________. sediments Check Answer

74 Question 19 When water and other minerals move through open spaced between larger sediments, gluing them together, ____________ occurs. cementation Check Answer

75 Question 20 _________ ___________ rocks are made from the remains of once – living plants or animals. Organic sedimentary Check Answer


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