RocksGroup6



Introduction Rocks can either be formed one of three ways : ~Sedimentry ~Igneous ~Metamorphic

The ways each rock are formed is the way each rock is classified. The Rock Cycle can be found below or on page 6 of your Earth Science Reference Table. Every rock can form from any other rock.

A Parent Rock- is the rock the before rock [ before it is transformed into another rock (also found in Felipe's presentation: all credit to Felipe)]

Igneous Rocks! Magma and Lava:

Magma: is molten rock found deep below the Earth's surface Magma is often a mix of molten rock dissolved gasses and mineral crystals. You can find: ~Oxygen ~Silicon ~Aluminum ~Iron ~Magnesium ~Calcium ~Potassium ~Sodium Are found both in the earths crust and in magma

~ The rocks must be heated to 800 to 1200 degrees Celsius before they melt. In nature these temperatures are reached in the upper mantle and lower crust. Therefore, the magma/lava is/has to be very hot to melt rocks and turn them into igneous rocks.

~ But they cool very fast, in fact when magma/lava cools rapidly, the newly formed rock gets a glassy texture and no mineral crystals show ~  A hot, molten mass of rock can solidify into solid rock overnight.

Lava: is magma when exposed to the oxygen/when a volcano erupts

~ How they are transformed: ~How the type of igneous rock that forms is based on the composition of the magma ~When the magma comes in contact with the air/flows on the Earth's surface

~When the rock cools at a very rapid pace [ when magma and minerals crystallize ] it forms a rock, which is also known as an Igneous rock ~igneous rocks that are cooled fast have a soft glassy texture to them

Textures of Igneous Rocks include: ~ Fine ~ Coarse Grain: ~ Very Coarse Grain: ~Glassy: ~ Non-Vesicular: no gas pockets in the rock ~Vesicular: Gas Pockets in the rock ~

Examples of Igneous rocks are: (Photo's taken from Geology.com)









The Igneous rock table shows the classification system for igneous rocks, you cna find this also on page 6 of your Earth Science Reference Tables or below:



To find the entire Earth Science Reference Tables Booklet online click here :

Sedimentary Rocks!

The way these rocks are formed are by Lithification, Compaction and Cementation **//__NOT BY WEATHERING AND EROSION!__//** Compaction: Lithification: Cementation: Weathering: Erosion: The movement of sediments using water, air, glaciers and gravity moves sediments.



Formation of Sedimentary Rocks ! ~Weathering and Erosion causes these rocks to be broken up, The peices that break off are called sediments ~ Sediments are carried by erosion unitl they find and "Glue" themselves to other sediments (also known as cementation) ~ The sediments as they are glued form layers, this is called bedding. Bedding can be Graded bedding which is when the particle sizes of the sediments are heavier and more coarse or Cross Bedding: is inclined layers across a horizontal surface, when this is lithified the cross-bedding still is preserved in the rock. ~The sediments are also compacted together. Heat and pressure play a very important role in creating sedimentry rocks

Examples of Sedimentry rocks are:











Metamorphic Rocks!

During metamorphism, a rock changes form while remaining solid.

Metamorphic Rocks are classified into two textural groups: Foliated and non-foliated
 * Metamorphic Textures**

Foliation - Layers and brands of minerals; Layering within a metamorphic rock Examples: Slate; Sheist

Non-Foliation- do not display the banding or layering that are present in foliated rocks Examples- Marble; Quartzite

Different combinations of temperature and pressures result in different grades of metamorphism
 * Grades Of Metamorphism**

Low Grade – Low temperatures and pressures and a particle suit of minerals and textures Low-grade metamorphism takes place at temperatures between about 200 to 320oC, and relatively low pressure. Low grade metamorphic rocks are characterized by an abundance of hydrous minerals (minerals that contain water, H2O, in their crystal structure).

High Grade – High temperatures and pressures and a different suit of minerals and textures High-grade metamorphism takes place at temperatures greater than 320oC and relatively high pressure. As grade of metamorphism increases, hydrous minerals become less hydrous, by losing H2O and non-hydrous minerals become more common.

ROCK SONG DESCRIBING EACH. :D @http://www.kidsknowit.com/educational-songs/play-educational-song.php?song=The%20Rock%20Family