Presentation on theme: "IGNEOUS ROCKS Pg 99 text book What you will learn Describe three ways that igneous rock forms. Explain how the cooling rate of magma."— Presentation transcript:
IGNEOUS ROCKS Pg 99 text book
What you will learn Describe three ways that igneous rock forms. Explain how the cooling rate of magma affects the texture of igneous rock. Distinguish between igneous rock that cools within Earth’s crust and igneous rock that cools at Earth’s surface.
Igneous rock begins as magma What is the origin of Igneous Rock?
There are three ways magma can form: 1.when rock is heated, 2.when pressure is released, 3.when rock changes composition. What are the ways that magma can form?
Put a drawing like this on pg 37 in your nb
The longer it takes for the magma or lava to cool, the more time mineral crystals have to grow. The more time the crystals have to grow, the larger the crystals. The larger the crystals are the coarser the texture of the resulting igneous rock is. What happens to magma when it cools at different rates?
The less time magma takes to cool, the less time crystals have to grow. Therefore, the rock that is formed will be fine grained. What happens to magma when it cools at different rates?
Fine-grained igneous rock contains very small crystals, or if the cooling is very rapid, it contains no crystals. What happens to magma when it cools at different rates?
What are the Compositions and Textures of Igneous Rock? What are examples of each type?
What is Intrusive Igneous Rock? Magma that cools and solidifies deep within the Earth’s crust.
What is Intrusive Igneous Rock? Magma that intrudes, or pushes, into surrounding rock below the Earth’s surface and cools.
What is Intrusive Igneous Rock? Usually has a coarse- grained texture because it is well insulated by surrounding rock and cools very slowly. The minerals that form are large, visible crystals.
What are the different masses of intrusive igneous rock named and why? Masses of intrusive igneous rock are named for their size and shape Plutons Batholiths Stocks Dikes
Plutons are large, irregular-shaped intrusive bodies. The largest of all igneous intrusions are batholiths. Stocks are intrusive bodies that are exposed over smaller areas than batholiths. Dikes sheetlike intrusions that cut across previous rock units. Sills are sheetlike intrusions that are oriented parallel to previous rock units. Plutons Batholiths Stocks Dikes Sills
Where would I find Extrusive Igneous Rock? Magma that erupts, or extrudes, onto the Earth’s surface. Extrusive rock is common around volcanoes.
Lava cools quickly on the surface and contains very small crystals or no crystals. What type of texture do extrusive igneous rock have?
Does lava always come from volcanoes? Lava does not always flow from volcanoes. Sometimes lava erupts and flows from long cracks in the Earth’s crust called fissures.
Where do we find fissures? Lava flows from fissures on the ocean floor at places where tension is causing the ocean floor to be pulled apart. When a large amount of lava flows out of fissures onto land, the lava can cover a large area and form a plain called a lava plateau.
Sedimentary Rock Pg 44 in nb Pg 102 in tb
What You Will Learn Describe the origin of sedimentary rock. Describe the three main categories of sedimentary rock. Describe three types of sedimentary structures.
Rock and mineral fragments called sediment What are the origins of Sedimentary Rocks? sediment plume from Moore Creek entering Dog River.
What are the agents of weathering that make sediment? 1.Wind 2. Water 3. Ice 4.Sunlight 5.Gravity
How do sediments move from one place to another? Through the process of erosion.
1.Layers of sediment are deposited, they cover older layers. 2. Older layers become compacted. 3. Dissolved minerals separate from water that passes through the sediment. 4. Dissolved minerals form a natural cement 5.Cement binds the rock and mineral fragments together. How are sedimentary rocks formed?
Sedimentary rock forms at or near the Earth’s surface. It forms without the heat and pressure that are involved in the formation of igneous and metamorphic rocks.
Sedimentary rock is classified by the way it forms. Clastic, Chemical, and Organic How is sedimentary rock is classified?
Clastic sedimentary rock is made of fragments of rocks cemented together by a mineral such as calcite or quartz. What is clastic Sedimentary Rock?
By the size of the fragments from which the rock is made. How is clastic sedimentary rock is classified? Pg 103
Chemical sedimentary rock forms from solutions of dissolved minerals and water. How is chemical sedimentary rock formed? Halite, one type of chemical sedimentary rock, is made of sodium chloride, NaCl, or table salt.
What is Organic Sedimentary Rock and what are some examples. Limestone forms from the remains, or fossils, of animals that once lived in the ocean. Coal forms underground when partially decomposed plant material is buried beneath sediment and is changed into coal by increasing heat and pressure.
fossiliferous limestone coalcoal
What are some Sedimentary Rock Structures? Stratification is the process in which sedimentary rocks are arranged in layers. Ripple marks, record the motion of wind and water waves on lakes, oceans, rivers, and sand dunes in features called Structures called mud cracks
Metamorphic rocks pg 106 text pg 48nb
Origins of Metamorphic Rock If the temperature or pressure of the new environment is different from the one in which the rock formed, the rock will undergo metamorphism. The word metamorphism comes from the Greek words meta, which means “changed,” morphos, which means “shape.”
Contact metamorphism is a change in the texture or structure of a rock resulting from the contact of invading magmatic material. Texture and structure of metamorphic rocks
Regional metamorphism is metamorphism that affects rocks over large areas, instead of in only a local area.
Hornfels is a fine-grained nonfoliated metamorphic rock with no specific composition. It is produced by contact metamorphism. Hornfels is a rock that was "baked" while near a heat source such as a magma chamber, sill or dike.
Regional metamorphic area
The minerals calcite, quartz, and hematite combine and recrystallize to form the metamorphic mineral garnet. P.108
Scientists can understand a metamorphic rock’s history by observing the minerals the rock contains. Theses minerals are called index minerals p108 index minerals,
Textures of Metamorphic Rock The texture of metamorphic rock in which the mineral grains are arranged in planes or bands Foliated.
Textures of Metamorphic Rock The texture of metamorphic rock in which the mineral grains are not arranged in planes or bands Nonfoliated.
The effects of metamorphism depend on the heat and pressure applied to the rock. see what happens to shale, a sedimentary rock, when it is exposed to more and more heat and pressure.. Pg 109
Metamorphic Rock Structures Deformation is a change in the shape of a rock caused by a force placed on it. These forces may cause a rock to be squeezed or stretched.
These large folds occur in metamorphosed sedimentary rock along Saglet Fiord in Labrador, Canada
Slate is a fine-grained, foliated metamorphic rock that is created by the alteration of shale or mudstone by low-grade regional metamorphismmetamorphic rockshale
Shale sedimentary rock Slate metamorphic rock created by the alteration of shale or mudstone by low-grade regional metamorphism
Gneiss is foliated metamorphic rock that has a banded appearance and is made up of granular mineral grains.
Granite igneous rock Gneiss metamorphic rock
Marble is a non-foliated metamorphic rock that is produced from the metamorphism of limestone.
Limestone sedimentary rock Marble metamorphic rock
Quartzite is a non-foliated metamorphic rock that is produced by the metamorphism of sandstone. It is composed primarily of quartz.
Sandstone sedimentary rock Quartzite metamorphic rock