RocksGroup7

http://www.rocksandminerals.com/rockcycle.htm [] []

Bowens Reation Series is: As hot **[|magma]** cools, it undergoes specific reactions. Bowen's reaction series describes the **[|temperature]****Bowen's reaction series depicts mineral formation in a cooling magma. The discontinuous side depicts mineral formation at decreasing temperatures. The continuous side depicts a solid solution series. As the magma cools there is a trend towards molecular complexity. As the temperature cools, viscosity increases.** Illustration by Argosy. The Gale Group. dependent formation of **[|minerals]** as magma cools. **[|Rocks]** formed from magma are **[|igneous rocks]**, and minerals crystallize as magma cools. The temperature of the magma and the **[|rate]** of cooling determine which minerals are stable (i.e., which minerals can form) and the size of the mineral crystals formed (i.e., texture). The slower a magma cools, the larger crystals can grow. The **rock cycl**e is a model that describes the formation, breakdown, and reformation of a rock as a result of sedimentary, igneous, and metamorphic processes.



Igneous rocks are called fire rocks and are formed either underground or above ground. Underground, they are formed when the melted rock, called magma, deep within the earth becomes trapped in small pockets. As these pockets of magma cool slowly underground, the magma becomes igneous rocks. Igneous rocks are also formed when colcanoes erupt, causing the magma to rise above the earth's surface. When magma appears above the earth, it is called lava. Igneous rocks are formed as lava cools above ground.
 * Igneous Rocks : Formed from the cooling of molten rock.


 * Igneous rocks are the oldest kind of rock.
 * Igneous rocks are formed deep inside the earth where the temperature is very high.
 * The [|minerals]in the earth are in liquid form and are called magma.
 * Magma is squeezed around inside the earth and as it pushes towards the surface of the earth, it starts to cool. As it cools, it turns to solid igneous rock.
 * Sometimes the magma cools very slowly and forms rocks.
 * Igneous rocks that cool slowly deep in the earth are called Intrusive igneous rocks and have large crystals. (Granite)
 * Sometimes the magma erupts from a volcano. Magma is called lava when it reaches the earth's surface. Lava cools quickly and forms igneous rocks.
 * Igneous rocks that cool quickly on the surface of the earth form rocks with small crystals called extrusive rocks. (Basalt, obsidian)
 * Sometimes extrusive igneous rocks look like glass and have no crystals or mineral particles.

These little bits of our earth are washed downstream where they settle to the bottom of the rivers, lakes, and oceans. Layer after layer of eroded earth is deposited on top of each. These layers are pressed down more and more through time, until the bottom layers slowly turn into rock.
 * Sedimentary Rocks : Formed in layers as the result of moderate pressure on accumulated sediments.


 * 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.

For examples of sedimentary rocks, take a look at these:


 * < **sandstone** ||<  ||< **limestone** ||<   ||< **shale** ||<   ||~   ||< **gypsum** ||



Sandstone - very prevalent sedimentary rock

Conglomerate

Metamorphic Rocks: Formed from older "parent" rock (either igneous or sedimentary) under intense heat and/or pressure at considerable depths beneath the earth's surface. Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks. How do sedimentary and igneous rocks change? The rocks are under tons and tons of pressure, which fosters heat build up, and this causes them to change. If you exam metamorphic rock samples closely, you'll discover how flattened some of the grains in the rock are.


 * Metamorphic rocks are rocks that have changed from one form to another.
 * These rocks form deep in the earth where the it is very hot and there is a lot of pressure.
 * If a rock is heated and squeezed for millions of years, it can turn into a new kind of rock.

**Metamorphic rock is a result of an existing rock undergoing extreme heat or pressure. Metamorphic rocks often retain some characteristics of the parent rock from which it came from. The usual depth for metamorphism is above igneous depths (50-250) and below sedimentary depths (2km).Metamorphic means change, and metamorphic rock changes over a period of time.**
 * There are three types of rocks. There are igneous,sedimentary and metamorphic rock. Heat and pressure can change an igneous rock, granite, into gneiss (nise). It can change a sedimentary rock, shale, into slate, a metamorphic rock. And it can also change another sedimentary rock, limestone, into marble.**