RocksGroup1

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**Igneous Rocks **
 **Formation of Igneous Rocks:** -[|formed] by magma being cooled and becoming solid. -they may form with or without crystallization -either below the surface as intrusive rocks or on the surface as extrusive rocks

-formed from magma that cools and solidifies within the Earths crust or mantle -if the magma cools slowly then the rocks become coarse grained -can occupy huge areas of Earth surface if the inside of a major mountain is in Igneous rock and it starts eroding -have crystals because of the slow cooling
 * Intrusive Rocks: **

**Extrusive Rocks:**  -formed from magma that cools and solidifies outside the Earths crust -since the lava cools and crystallizes rapidly it is fine grained -do not have any crystals because the lava cools so fast that it prevents then from forming Cooling magma -harder to distinguish different types of extrusive igneous rocks then intrusive igneous rocks

**Basaltic Rocks:** -formed by decompression melting of the mantle -dark colored rocks, is rich in iron and magnesium -mainly composed of plagioclase and pyroxene minerals   -common type of intrusive and igneous rock - usually have medium to coarse grain -can be pink to dark gray or even black -nearly always massive, hard, tough -commonly used as construction stone 
 * Granite Rocks: **

**Classification:** - Igneous rocks are determined by it's texture, chemical composition, geometry of the shape, mineralogy, and the mode of occurrence -Feldspar's, Quartz or Feldspathoids, Olivines, pyroxenes, Amphilboles and Micas are important minerals in the formation of almost all ingeous rock and are basic classification of these rocks

- A process where as magma cools and crystalizes, minerals form in predictable patterns - invented by N.L. Bowen - Divided into two groups, continuous, and discontinuous    - the rocks on top are crystalized first.  **Other facts about Igneous rocks:** [|- make up about 90% of the Earth's crust] 
 * Bowen's reaction series **

Earth Science Reference Table: <span style="font-family: 'Trebuchet MS',Helvetica,sans-serif; font-size: 80%;">In the sixth page of the Earth Science Reference Table you can find a chart named, __Scheme for Igneous Rock Identification__. This chart shows, if the rock is intrusive or extrusive, its chrystal size, texture, shade of color, density, and compositon. These charastics help to find the rock type. <span style="font-family: 'Trebuchet MS',Helvetica,sans-serif;">

<span style="color: #0b0404; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 80%; text-align: center;"><span style="color: #002bf5; display: block; font-family: 'Arial Black',Gadget,sans-serif; font-size: 150%; text-align: center;">**Sedimentary Rocks**

__<span style="color: #f90b0b; font-family: Verdana,Geneva,sans-serif; font-size: 110%;"> Sediments __ - small pieces of rock that are moved when deposited by water, wind, glaciers, and gravity.

//Weathering// is the breaking down of particles.

occurs when thee minerals in a rock are dissolbed or otherwise cemically changed.
 * Chemical weathering ** -

minerals remain chemiclly unchanged but change physically.
 * Physical weathering- **

is the removal and transport of sediments. The our main agents of erosion are wind, moving water, gravity, and glaciers. During erosion, these sediments are transported to different locations.
 * Erosion ** -

S**edimentary** **rocks** .- When sediment are glued together

**__//Depostition//__**: When transported sediments are deposited on the ground or sink to the bottom of a body of water, deposition occurs. Sediments are deposited in layers with the largest grains at the bottom and the smallest grains on top.

__Lithification__ - As more sediment is deposited in an area, the bottom layers are subjected to increasing pressure and temperature. These conditions cause lithification, the physical and chemical processes tht transform sediments into sedimentary rocks. - Lithification begins with compaction.

**Compaction-** is the weight of overlying sediments forcing the sediment grains closer together, causing physical changes. also occurs when mineral growwth glues sediment grains together into solid rock. <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 120%;">
 * Cementation** -

<span style="font-family: Verdana,Geneva,sans-serif;">** Cross bedding- is formed as inclined layers of sediment are deposited across a horizontal surface. **