RocksGroup3

Sedimentary Rocks: By Michael Arnold, Rob Meade & Adam Montesinos

-What is a rock? A rock is a solid. It is naturally occuring. Rocks are made up of minerals or mineral like matter.

- What are the three different types of rocks? The 3 types of rocks are Sedimentary rocks, Metamorphic rocks and Igneous Rocks.

- How does each form? http://www.priweb.org/ed/pgws/geology/sed_rocks.html

-Sedimentary Rocks Form on the earth's surface.

-Metamorphic Rocks were formed many kilometers below ground level. Many years of erosion began to uncover these rocks, that were hidden once before.

-Igneous Rocks form when Lava and or Magma cool and minerals begin to crystallize.

-Rock Cycle: The Rock Cycle is a set of steps used to describe the changes that rocks have on earth.

- Definition - layered rocks that form at the surface of the earth either: - by deposition of sediment particles from air, water, or ice environments (clastic or detrital rocks) or

- by precipitation of minerals from solution in water (nonclastic or chemical rocks).  
 *  Making sediment into rock ( **lithification ** ) -
 * **Compaction** - sediment is squeezed and crushed until it holds together.
 * **Cementation** - minerals are precipitated (crystallized) in the pore spaces between sediment particles so that they become glued together.

-The clastic sedimentary rocks, are formed from the abundant deposits of loose sediments that accumulate on Earth's surface.

- Klastos, which means broken is where the word clastic comes from. These rocks can be classified according to the sizes of their particles.

- Coarse-grained rocks are sedimentary rocks consisting of gravelsized rock and mineral fragments are classified as coarse-grained rocks.

-Conglomerates have rounded, gravel-sized particles. Because of its relatively large mass, gravel is transported by high-energy flows of water, such as thos generated by mountain streams, flooding rivers, some ocean waves and glacial meltwater.

- In contrast, breccias are composed of angular, gravel-sized particles. The angularity indicates that the sediments from which they formed did not have time to become rounded.

-Medium grained rocks have stream and river channels, beaches and deserts often contain abundant sand-sized sediments. Sedimentary rocks that contain sand-sized rock and mineral fragments are classified as medium-grained clastic rocks.

- Bio chemical sedimentary rocks are formed from the remains of once-living organisms. The most abundant of these rocks is limestone, which is composed primarily of clacite. Some organisms that live in the ocean use the calcium carbonate that is dissolved in sea water to make their shells.

Classification of clastic sedimentary rocks -
 * **conglomerate ** = rounded by long transport distance || [[image:http://www.csun.edu/~khurst/ES300/Fritche/300CGtn.jpg width="188" height="150" align="center" link="http://www.csun.edu/~khurst/ES300/Fritche/300Conglomerate.html"]]

||
 * 
 * breccia** = angular due to short transport distance || [[image:http://www.csun.edu/~khurst/ES300/Fritche/300brecciatn.jpg width="141" height="150" align="center"]]

||

   || ||
 * ** Particles from 2 to 1/16 mm in size ( **<span style="font-family: Helvetica,Arial;">sand **<span style="font-family: Helvetica,Arial;"> ) = **<span style="font-family: Helvetica,Arial;">sandstone **

Very thinly layered = **<span style="font-family: Helvetica,Arial;">shale **<span style="font-family: Helvetica,Arial;"> || || Shale is the world's most abundant sedimentary
 * Particles <1/16 mm in size ( **<span style="font-family: Helvetica,Arial;">mud **<span style="font-family: Helvetica,Arial;"> ) -
 * Unlayered to moderately layered = **<span style="font-family: Helvetica,Arial;">mudstone **<span style="font-family: Helvetica,Arial;"> ||  ||

rock ||  ||

<span style="font-family: Helvetica,Arial;"> || || <span style="font-family: Helvetica,Arial;"> || || <span style="font-family: Helvetica,Arial;"> || ||
 * If made from accumulated animal and/or plant parts they are named according to the composition of the sediment -
 * ** Made of macroscopic calcite shell fragments = **<span style="font-family: Helvetica,Arial;">limestone || [[image:http://www.csun.edu/~khurst/ES300/Fritche/300limestonetn.jpg width="151" height="150" link="http://www.csun.edu/~khurst/ES300/Fritche/300fossils.html"]] ||
 * Made of microscopic calcite shell fragments = **<span style="font-family: Helvetica,Arial;">chalk **
 * ** Made of macroscopic carbonized plant parts = **<span style="font-family: Helvetica,Arial;">coal || [[image:http://www.csun.edu/~khurst/ES300/Fritche/300anthracitetn.jpg width="199" height="150"]] ||
 * Made of microscopic quartz plant parts = **<span style="font-family: Helvetica,Arial;">diatomite **
 * ** Where diatomite is hard and recrystallized = **<span style="font-family: Helvetica,Arial;">chert **