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SEDIMENTARY ROCK FACTS

. Sedimentary rocks are made from sediments.

. Sediments are small pieces of other rocks. They turn into pebbles, gravel, sand and clay.

. Rocks are always being broken into smaller pieces called sediments and worn away (eroded) by wind and water.

. These little pieces flow along in rivers and streams or blow over the land with the wind and settle in a new place.

. As they settle, they pile up and form layers.

. After long periods of time, the pieces become pressed together and form solid rock called sedimentary rock.

. Sedimentary rocks are usually formed in water.

. Sedimentary rocks are found all over the world.

. Many fossils are found in sedimentary rock.

HOW THEY ARE FORMED


Sedimentary rocks are made out of sediments, I sed- it and -I ment it!

Sedimentary rocks are those formed from the compaction and cementation of fragments of pre-existing rocks or plant and animals remains ( fossils). Also sedimentary rocks are born cool at the Earth's surface, mostly under water. That is why we find dinosaur fossils and early sea life. For millions of years, pieces of our earth have been eroded (broken down) and worn away



by wind and water. These little bits of our earth are washed downstream where they settle to the bottom of the the body of water they so happen to be in. Layer after layer of eroded earth is deposited on top of each other. These layers are pressed down more and more through time, until the bottom layers slowly turn into rock. lithification is the compaction and cementation of rock fragments that form sediments from rocks. sandstone is made up of sandstone particles-shale is going to feel smooth made of compacted mud. chemical (crystalline) sedimentary rocks formed from the precipitation of a mineral solution the main causes for dissolved minerals to precipitate or drop out of the water, is an evaporation.


How to tell if YOUR rock is Sedimentary



Often contains fossils
May react with acid
external image bullet2.gif Often has layers, flat or curved
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Usually composed of pieces cemented or pressed together
external image bullet2.gif Has great color variety
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Particle size may be the same or vary
Usually has pores between pieces
May have cross-bedding, mud cracks, worm burrows, raindrop impressions



IGNEOUS ROCKS


Igneous rock is formed by magma (molten rock) cooling and becoming solid. Igneous rock may form with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive rocks. This magma can be derived from partial melts of pre-existing rocks in either a planet's mantle or crust

Metamorphic rocks.
Metamorphic rock is the result of the transformation of an existing rock type,
The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides us with very valuable information about the temperatures and pressures that occur at great depths within the Earth's crust Some examples of metamorphic rocks are gneiss, slate, marble, schist, and quartzite.