ROCK FORMATION
Rock formations are created millions of years of weathering and erosion by the elements such as heat, wind, rain and occasional volcano.
Our planet is chock full of beautiful and bizarre rock formation. Access the
link to some incredible pictures of rock formation
The main types of rock and the differences among them have to do with how they are formed.
IGNEOUS ROCKS
Examples
Granite,
Basalt, Obsidian, Pumice
Igneous rocks are formed from molten magma or lava. The word, igneous means,
"fire". All igneous rock starts deep in the earth as hot, molten magma.
If the magma cools and hardens inside the earth it is called "intrusive"
rock. These rocks cool slowly and have large crystals. When the magma comes
out of the earth's crust through a volcano, it is called "extrusive".
It cools off quickly, and the crystals that form are very small.
Molten, or hot, liquid rock is called MAGMA when it is still inside the earth,
but once it comes out through a volcano it is called LAVA.
SEDIMENTARY ROCKS
Examples
Limestone , Jasper,
Gypsum, Conglomerate, Sandstone
Every minute of every day, rocks are being worn down by wind and rain. Tiny
grains of dirt, sand, mud and clay are worn off and washed into streams, rivers,
lakes and oceans. When these tiny bits of sand and dirt settle to the bottom
of the water, they are called sediment.
Minerals in the water and microscopic, or very tiny sea animals also get mixed
in with the dirt and sand to form the sediment. Every day more sediment piles
on top of what is already there.
After thousands and millions of years we end up with a really deep pile
of sediment. The weight and pressure from all the stuff on top turns the
sediment on the bottom into sedimentary rock!
METAMORPHIC ROCKS
Example
Quartz, Amethyst,
Marble, Slate, Gneiss, Graphite
Metamorphic rocks are formed when other kinds of rocks are changed by great
heat and pressure inside the earth.
The word "metamorphic" means changed. Think of metamorphic rocks as
recycled rocks. When igneous, sedimentary or even metamorphic rocks get buried
deep beneath the surface of the earth, over millions of years the heat and pressure
inside the earth change them into something else.
Limestone can be changed to marble, sandstone can be changed into quartzite,
and shale can be changed to slate. It's just another example of how the earth
is constantly changing!
TRANSPORTATION OF ROCKS
As rocks are broken down by chemical and physical forces, particles become
increasingly smaller. The particles are transported through rivers and
by wind. The three main sizes of soil include sand, silt, and clay. Soil
formation occurs due to the change in particle size, organic matter, and
the movement of elements and minerals. The four major influences on soil
are weathering, climate, land surface, and living organisms.
On Internet sites you'll find more information
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