THE STUDY OF ROCKSHOW ROCKS ARE

FORMED

THE EARTH'S CRUSTThe whole earth is made of rocks & minerals.

Inside the earth there is a liquid core of molten rock and on the outside there is a hard crust.

If you compare the earth to an egg, the shell on an egg is like the crust on the earth.

The crust is made up of rocks and minerals. Much of the crust is covered by water, sand, soil and ice.

If you dig deep enough, you will always hit rocks. Below the loose layer of soil, sand & crumbled rocks found on Earth is

bedrock, which is a solid rock

The Crust makes up less than 1% of the Earth’s mass (0.4%) It is made of oxygen, magnesium aluminum, silicon calcium, sodium potassium, iron. There are 8 elements that make up 99% of the Earth’s crust. The continents are about 35 km thick and the ocean floors are about 7 lm thick. The Mantle is the solid casing of the Earth and is about 2900 km thick. It makes up about 70% of the Earth’s mass (68.1%). It is made up of silicon, oxygen, aluminum and iron. The Core is mainly made of iron and nickel and makes up about 30% of the Earth’s mass (31.5%). The Outer Core is 2200 km thick and is liquid and the Inner core is 1270 km thick and is solid.  

ROCKSThe rocks you see around you - the mountains, canyons & riverbeds, are all made of minerals. A rock is made up of 2 or more minerals. Think of a chocolate chip cookie as a rock. The cookie is made of flour, butter, sugar & chocolate. The cookie is like a rock and the flour, butter, sugar & chocolate are like minerals. You need minerals to make rocks, but you don't need rocks to make minerals. All rocks are made of minerals. •For a LIST of ROCKS, check out Wikipedia's List of Rocks http://en.wikipedia.org/wiki/List_of_rocks •For some PHOTOGRAPHS of ROCKS, look here. MINERALS

ROCKS•MINERALS

MINERALSA mineral is composed of the same substance throughout. If you were to cut a mineral sample, it would look the same throughout. There are about 3000 different minerals in the world. Minerals are made of chemicals - either a single chemical or a combination of chemicals. There are 103 known chemical elements. Minerals are sorted into 8 groups. Some common examples have been listed for each. Native Elements ~ copper, silver, gold, nickel-iron, graphite, diamond Sulfides ~ sphalerite, chalcopyrite, galena, pyrite Halides ~ halite, fluorite Oxides & Hydroxides ~ corundum, hematite Nitrates, Carbonates, Borates ~ calcite, dolomite, malachite Sulfates, Chromates, Molybdates, Tungstates ~ celestite, barite, gypsum Phosphates, Arsenates, Vanadates ~ apatite, turquoise Silicates ~ quartz, almandine garnet, topaz, jadeite, talc, biotite mica  

CRYSTALSCrystals are minerals that have had the chance to grow in the shape that they were meant to be. Just like your DNA determines the colour of your eyes, how tall you will get to be and the shape of your bones, the chemicals that a mineral is made of determines what shape it gets to be. We can tell different minerals apart by what crystal shape they are. Sometimes minerals form in spaces where there is not a lot of room, so they don't have a crystal shape. When there is just a big hunk of a mineral, it is called a massive mineral. If there is a definite shape with easy to see flat sides, it is called a mineral crystal. Most of the earth's crystals were formed millions of years ago. Crystals form when the liquid rock from inside the earth cool and harden. Sometimes crystals form when liquids underground find their way into cracks and slowly deposit minerals. Most mineral crystals take thousands of years to "grow" but some like salt (halite) can form so quickly that you can watch them grow at home! Some people think of crystals as clear pretty rocks that are used for jewelry. Amethyst is a very common quartz crystal. Crystals do not have to be clear, but those are the kinds you will usually see in the stores.  

CRYSTALS

SOIL, SAND & DIRTWhen rocks break down into smaller & smaller pieces, they turn into sand. If you look at the sand under a microscope, you will see that sand is made up of the same minerals as the rocks that the sand came from. When plants start to sprout up in sand, it is turning from being just small bits of rock to being soil. For

THE ROCK CYCLERocks are constantly being formed, worn down and then formed again. This is known as the Rock Cycle. It is like the water cycle but it takes a lot longer. It takes thousands and millions of years for rocks to change. Rocks are divided into 3 Types. They are classified by how they were formed. IGNEOUS SEDIMENTARY METAMORPHIC Some good sites that help explain this are:The Stupid Page of Rocks   Describes metamorphic, sedimentary & igneous rocks Rocks and the Rock Cycle A well written description of the Rock Cycle.

IGNEOUS ROCKSIgneous means made from fire or heat. When volcanoes erupt and the liquid rock comes up to the earth's surface, then new igneous rock is made. When the rock is liquid & inside the earth, it is called magma. When the magma gets hard inside the crust, it turns into granite. Most mountains are made of granite. It cools very slowly and is very hard.When the magma gets up to the surface and flows out, like what happens when a volcano erupts, then the liquid is called lava. Lava flows down the sides of the volcano. When it cools & turns hard it is called obsidian, lava rock or pumice - depending on what it looks like. •Igneous rocks form when molten lava (magma) cools and turn to solid rock. The magma comes from the Earth’s core which is molten rock . The core makes up about 30% of the Total Earth Mass (31.5%) •Obsidian is nature’s glass. It forms when lava cools quickly on the surface. It is glassy and smooth. •Pumice is full of air pockets that were trapped when the lava cooled when it frothed out onto the surface. It is the only rock that floats.  •There are 5 kinds of igneous rocks, depending on the mix of minerals in the rocks. •Granite

IGNEOUS ROCKS

SEDIMENTARY ROCKSWhen mountains are first formed, they are tall and jagged like the Rocky Mountains on the west coast of North America.

Over time (millions of years) mountains become old mountains like the Appalachian Mountains on the east coast of Canada and the United States. When mountains are old, they are rounded and much lower. What happens in the meantime is that lots of rock gets worn away due to erosion. Rain, freeze/thaw cycle, wind and running water cause the big mountains to crumble a little bit at a time. Eventually most of the broken bits of the rock end up in the streams & rivers that flow down from the mountains. These little bits of rock & sand are called sediments. When the water slows down enough, these sediments settle to the bottom of the lake or oceans they run into. Over many years, layers of different rock bits settle at the bottom of lakes and oceans. Think of each layer as a page in a book. One piece of paper is not heavy. But a stack of telephone books is very heavy & would squish anything that was underneath. Over time the layers of sand and mud at the bottom of lakes & oceans turned into rocks. These are called sedimentary rocks.

SEDIMENTARY ROCKS

Rocks

Rock Cycle

Elephant Rocks

SLIDING ROCKS

SLIDIN

G

ROCKS

MOVING ROCKS