jardina-conelway elementary chapter 2 rocks. jardina-conelway elementary three rock types igneous...

Jardina-Conelway Elementary

Chapter 2

Rocks


Three Rock Types

Igneous

Sedimentary

Metamorphic


Igneous Rocks: A Hot Item

Rocks are made up of minerals.

The word igneous comes from the Latin word for “fire”

Igneous rocks form when hot, melted rock material cools and hardens.

Molten rock that forms deep below the earth is called magma.


Igneous Rocks Formed From Magma

Magma rises because it is less dense than the material around it.

As it rises it sometimes cools before it reaches the surface.

The magma cools slowly, allowing mineral grains or crystals to form slowly…

Mineral grains are large in rocks formed from magma.


Igneous Rocks Formed From Lava

Magma that reaches the earth’s surface is called lava.

An opening through which lava flows is called a volcano.

When lava cools on the earth’s surface it forms igneous rocks.


Igneous Rocks – Lava Formed

Lava cools much quicker than magma because it is on the earth’s surface.

How would this affect the size of the mineral grains (crystals) found in lava rocks compared to rocks formed from magma?

Basalt Lava Basalt Lava

ObsidianRhyolite


Sedimentary Rocks: Rocks Formed From Pieces

Sedimentary rocks are formed at earth’s surface when sediments harden into rock.

Sediments include bits of rocks, minerals, and organic materials (what are organic materials?)


Types of Sedimentary Rocks

Clastic: pieces of rocks, minerals, and organic materials are cemented together.

Chemical: form when water rich in dissolved minerals evaporates, leaving the minerals behind or when chemical changes form new minerals.

Organic: form from the remains of plants and animals or from parts, such as shells, of organisms.


Clastic Sedimentary Rocks

Most clastic sedimentary rocks form when wind, water, or ice carry and drop sediments and then they become compacted or cemented together.

Cementation takes place when the water dries and the minerals and loose sediment bind together.


Chemical Sedimentary Rocks

Rocks that form when water rich in dissolved minerals evaporates Roock Gypsum- forms

when H²O evaporates. Rock Salt- (almost

pure halite) is known to you as table salt.

Limestone is a "chemical" sedimentary rock that is composed mostly of calcite (CaCO3) that precipitates from seawater.


Organic Sedimentary Rocks

Form from the remains of plants and animals or from parts (shells) of organisms.

Anthracite coal forms when bits of dead plants are compacted over long periods of time.

The squeezing removes the water and leaves behind the carbon that makes up the coal.


Metamorphic Rocks

Metamorphic – “To Change Form”

Are like sedimentary rocks because they form from existing rocks

Are like igneous rocks because both kinds can form at high temperatures and pressures.

So how are they different than the other 2 types of rocks that we have discussed?


Metamorphic Rocks: Metamorphic rocks are

new rocks that form from existing rocks because of changes caused by heat, pressure, or chemicals.

Change from one type of rock to another is referred to as metamorphism.

http://images.google.com/imgres?imgurl=http://www.windows.ucar.edu/earth/geology/images/rock_cycle_ani4.gif&imgrefurl=http://www.windows.ucar.edu/tour/link%3D/earth/geology/rocks_intro.html&h=400&w=238&sz=111&hl=en&start=19&tbnid=6PSVuFyIO6sbbM:&tbnh=124&tbnw=74&prev=/images%3Fq%3Dmetamorphic%2Brock%2Bchange%26gbv%3D2%26svnum%3D10%26hl%3Den


Changes in Metamorphism

The changes that occur in metamorphism can result from three different sets of conditions. Contact Metamorphism- hot magma or lava comes in

contact with rock and gets “baked.” (change occurs from just the heat)

Regional Metamorphism- occurs in rocks buried deep below the earth’s surface where temp. and pressure change the rocks texture and composition.

Burial Metamorphism- causes the least amount of change, occurs when the weight of rocks and sediment burying a rock put pressure on it.


Classifying Metamorphic Rocks

M.R. are classified as banded or nonbanded.

Banded M.R.’s mineral grains are lined due the heat and pressure that formed the rocks

Nonbanded M.R.’s texture is described as massive and do not have mineral grains aligned.


All About Rocks and Minerals (23:20)

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Rock Quarries

A quarry is a mine from which rocks can be removed.

Rock is removed from quarries in two forms Dimension stones- slabs

of rock removed for specific shapes and sizes.

Crushed stone- bits and pieces of rocks that are primarily used in concretes and cements.


A Ton of Bricks

Bricks aren’t actually rocks because they are not formed by nature.

Bricks are made from clays and sediments.

Bricks have been used by people for over 60 centuries.

How is the way that bricks are created similar to that of how metamorphic rocks as well as sedimentary rocks are formed?

Adobe Brick House


Coal: A Fossil Fuel

A fossil fuel is a material formed from plant or animal remains that can be burned for energy.

Millions of years of high temperatures and pressure have “squeezed” and changed these remains forming coal.


Types of Coal

Bituminous Coal- provides the most energy of all the types of coal, but is very harmful to our environment.

Anthracite Coal- burns much cleaner and longer, but does not provide as much energy.


The Rock Cycle


The Rock Cycle

Any kind of rock can change into another type of rock and not just by metamorphism.

Melting and pressure can change one rock type to another. The series of changes that rocks undergo is called the “Rock Cycle.”


From one type to another!!!

Sedimentary to Metamorphic High temperatures and pressures within the earth

change sedimentary into metamorphic rocks. Metamorphic to Igneous

The melting of rocks (metamorphic) into molten rock and the cooling of them again into igneous rocks, shows the change of yet another type of rock into another.

Igneous to Sedimentary Weathering is the breaking up of rocks into sediments.

Any igneous rocks the cool on the surface of the earth can become sediment bits through the process of weathering. The sediments are then compacted and cemented together naturally to form sedimentary rocks.

jardina-conelway elementary chapter 2 rocks. jardina-conelway elementary three rock types igneous...

Documents

lava rocks

new rocks

bits of rocks

pieces of rocks

piecessedimentary rocks

types of rocks

fireigneous rocks form

new minerals