Part 1 Rock Cycle and Igneous Rocks

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By: hikmat1111 (17 month(s) ago)

good work and long breath I wonder if I can upload my presentation in kurdish language

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Chapter 3 : 

Chapter 3 Rocks!

Section 3.1 : 

Section 3.1 Objectives Define the term “rock” Identify the three major types of rocks and explain how they differ Describe the rock cycle List the forces that power the Earth’s rock cycle

Why study rocks? : 

Why study rocks? Earth processes such as volcanic eruptions, mountain building, weathering, erosion, and earthquakes involve rocks and minerals What rocks exist in an area and what the rocks are made of tells us the history of that area

Trivia : 

Trivia Rocks occupy 5/6 of the volume of the earth (that is over 80%!!!) Rocks make up 2/3 of the Earth’s mass The oldest rocks on the Earth are not actually from earth at all They are meteorites. Some are 4.5 billion years old.

What are rocks? : 

What are rocks? A rock is any solid mass of mineral or mineral like matter that occurs naturally as part of our planet All minerals are rocks Most rocks are made up of minerals Granite is an example Some rocks are made up of non-minerals Coal is an example

More about rocks : 

More about rocks Even when a rock such as granite is made up of many minerals, each of the minerals still retains their individual properties. Rocks can be inorganic in nature such as coal Rocks do not have to have a crystalline structure like minerals do. Obsidian and pumice are examples

Obsidian and Pumice : 

Obsidian and Pumice

Identifying Minerals : 

Identifying Minerals Rocks are classified into three groups based on how they were formed There are three major types of rocks Igneous rocks Magma or lava cools Sedimentary rocks Sediments are compacted and cemented Metamorphic rocks Rocks changed by pressure, heat, or solutions

The Rock Cycle : 

The Rock Cycle Earth is a system consisting of many interacting parts Interactions among Earth’s water, air, and land can cause rocks to change from one type to another The continuous processes that cause rocks to change make up the “rock cycle”

The Rock Cycle : 

The Rock Cycle

The Rock Cycle : 

The Rock Cycle Magma forms when rock melts deep beneath the Earth’s surface

The Rock Cycle : 

The Rock Cycle When magma or lava cools and solidifies, igneous rocks form

The Rock Cycle : 

The Rock Cycle Rocks at the Earth’s surface are broken down into smaller pieces called sediments

The Rock Cycle : 

The Rock Cycle When sediments are compacted and cemented, sedimentary rocks form

The Rock Cycle : 

The Rock Cycle Any type of rock that is changed by heat, pressure, or fluids becomes a metamorphic rock

Metamorphic Processes : 

Metamorphic Processes

Metamorphic Processes : 

Metamorphic Processes

Metamorphic Processes : 

Metamorphic Processes

Think about it! : 

Think about it! What happens when igneous rock is exposed at the Earth’s surface? It will undergo weathering Weathering is a process in which rocks are physically and chemically broken down by water, air, and living things The weathered pieces are called sediments Sediments are moved by air, water, gravity, and glaciers and eventually deposited someplace Sediments are eventually compacted and cemented together to become sedimentary rocks

Think about it! : 

Think about it! What would happen if sedimentary rocks were buried deep within the Earth? They will be subjected to increases in pressure and/or temperature Under extreme pressure and temperatures, sedimentary rock will change into metamorphic rock

Think about it! : 

Think about it! What happens if the pressure and temperatures that changed sedimentary rock to metamorphic rock were to get even greater? Additional pressure and higher temperatures can cause metamorphic rock to melt and form magma

Think about it! : 

Think about it! Can sedimentary rock become igneous rock without changing first to a metamorphic rock? No. Any change in temperature and/or pressure will cause the sedimentary rock to become a metamorphic rock

Other paths : 

Other paths If igneous rock stayed deeply buried and was subject to higher pressures and/or temperatures it could change into metamorphic rock If the temps and pressures were high enough the igneous rock could melt again and recrystallize into a new igneous rock

Other Paths : 

Other Paths Metamorphic and sedimentary rocks can be weathered and break into new sediments The new sediments will eventually compact and cement to form new sedimentary rocks These sedimentary rocks can become reburied to form new metamorphic rocks all over again

Energy : 

Energy Where does the energy come from to drive the Earth’s rock cycle? Processes driven by heat from the Earth’s interior are responsible for forming igneous and metamorphic rocks Weathering and the movement of weathered materials are external processes powered by energy from the sun External processes produce sedimentary rocks

Section 3.2 : 

Section 3.2 Objectives Compare and contrast intrusive and extrusive igneous rocks Demonstrate how the rate of cooling affects an igneous rock’s texture Classify igneous rocks according to texture and composition

Formation of Igneous Rocks : 

Formation of Igneous Rocks Igneous means “fire” Intrusive Igneous rocks form when magma hardens beneath the Earth’s surface. Inside the Earth so called “Intrusive Igneous Rocks” because the intrude into existing rocks

Intrusive Igneous Rocks : 

Intrusive Igneous Rocks Magma less dense than other rocks so it works its way to the surface As magma works its way to the surface it cools allowing elements to combine and form minerals The minerals grow in size forming a solid mass of interlocking crystals Granite is a common example of an intrusive igneous rock

Granite : 

Granite Granite can come in many different colors and varieties Granite is used to make countertops, floors, walls, tombstones, art, etc

Extrusive Igneous Rocks : 

Extrusive Igneous Rocks When magma reaches the surface it is called Lava When lava hardens, the rocks that form are called extrusive igneous rocks Outside the Earth so called “Extrusive Igneous Rocks” because the extrude onto the surface

Evolution of Magma : 

Evolution of Magma Magma before cooling

Evolution of Magma : 

Evolution of Magma Magma after some cooling

Evolution of Magma : 

Evolution of Magma Magma after more cooling

Classification of Igneous Rocks : 

Classification of Igneous Rocks Texture and composition are two characteristics used to classify igneous rocks Texture: appearance of an igneous rock based on its size, shape, and the arrangement of its interlocking crystals Composition: based on the proportions of light and dark minerals in the rock

Course-grained texture : 

Course-grained texture The rate of cooling strongly affects texture Slow cooling allows ions to move large distances Slow cooling results in large crystals This is called a “coarse-grained texture”

Fine-Grained Texture : 

Fine-Grained Texture If cooling is rapid, then the ions lose their motion and quickly combine This results in a large number of tiny crystals Rapid cooling results in rocks with small, interconnected mineral grains This is called Fine-grained texture

Glassy Texture : 

Glassy Texture If cooling is so rapid the ions don’t have time to arrange themselves into networks of crystals, then the ions are randomly distributed Rocks formed have a glassy texture Obsidian and Pumice are two examples

Porphyritic Texture : 

Porphyritic Texture When a large body of magma cools deep in the Earth there may be different rates of cooling within the magma So, different size crystals may all form in the same rock Rocks with different size crystals are called porphyritic texture

Granitic Composition : 

Granitic Composition A group of igneous rocks made up almost entirely of light colored silicate minerals such as quartz and feldspar About 10% may be dark silicate minerals These are the major rocks of the continental crust

Basaltic Composition : 

Basaltic Composition Contain many dark silicate minerals and plagioclase feldspar Rich in magnesium and iron Darker and denser than granitic rocks

Andesitic Compostion : 

Andesitic Compostion Have a composition between granitic and basaltic Named after common volcanic rock “andesite” About 25% dark silicate minerals Amphibole, pyroxene, biotite, and plagioclase feldspar are common minerals

Ultramafic : 

Ultramafic Peridotite is important igneous rock in this group Group is almost 100% dark silicate minerals Rare to find at Earth’s surface Much of upper mantle is believed to be made of peridotite

Bowen’s Reaction Series : 

Bowen’s Reaction Series

Classification of Major Igneous Rocks : 

Classification of Major Igneous Rocks