Sedimentary Rock



The first thing you will notice about sedimentary rocks are layers/groups of other rocks or other materials compressed together. There will be fine lines (as in sandstone) or lots of little rocks - like with Conglomerate

Clastic Sedimentary Rocks

Clastic sedimentary rocks are made primarily of other rocks. These include rocks like conglomerate, sandstone and shale.

Conglomerate (yes, it looks like rock fruitcake)
Congolmerate is formed by larger rocks being pressed together over time.
conglomerate.jpg

Sandstone
Sandstone is a generic term for any rock that is made of sand - which means sandstone is primarily made of silicate (usually quartz). There are different colors and types of sandstone. Depending on the makeup of the sandstone, the colors can differ widely, with whites, yellows, blacks, and reds. 2 different types of sandstone are arkose (made of 25% feldspar) or tuff (made of volcanic rock).
sandstone400.jpg

These rocks are formed with the movement of rock fragments. In a river, bigger particles (which form things like conglomerate rocks) settle first and become compacted or cemented together over time. The farther down the river (and also farther into an ocean if the rocks are in the ocean) the more fine the rock fragments are. Farther into a river, sandstone and shale are developed.

Clastic rocks aren't always moved by rivers or oceans. Ice (such as glaciers) can move rock fragments, as well as mudslides, rockfalls, rockslides, as well as dust storms.

Chemical Sedimentary Rocks

Chemical sedimentary rocks are developed after minerals fall out of a water or air solution. Limestone is developed from the collection of calcium carbonate (CaCO3).
Other chemical sedimentary rocks are formed from evaoporated minerals - such as rock salt (halite).

Rock Salt (Halite)
halite.jpg
This halite is used for many different things - composed of NaCl, it is broken down into table salt, used for salt treatment of roads that are covered in ice or snow,
and used for food seasonings. It is usually found in dry, arid parts of the Earth where ancient lakes or oceans evaporated and left behind the saline part of the water solution.



Organic Sedimentary Rocks

Organic sedimentary rocks are created over time with the compression of biochemical materials. When plants or animals die and are compressed together, they form things like coal. Coal, composed of carbon, is used as an energy source

Coal
250px-coal_anthracite1.jpg
Coal - this picture showing "anthracite" - is used as an energy source. Know commonly as a "fossil fuel" it is composed of biochemical things - such as plants or animals. Anthracite is rather dense in comparison to other coals (like bitimous coal), has few impurities and a high carbon count. It is highly lusterous (in comparison to bituminous). It is mined in places like Pennsylvania, and is sold at 2-3 times the price of other coals. An interesting side note - anthracite mines have been accidently set on fire - the most common one is in Centralia, PA. This mining town has had its mine burning since 1962 - Centralia, PA is now a ghost town.

bituminous.jpg
Pictured: Bituminous Coal. Notice the lack of luster in comparison to anthracite. There is also sub-bituminous, which is a lesser grade of bitumious coal.

lignite.jpg
Pictured: Lignite Coal. Very low luster, and a very low grade of coal. Very cheap, but not as good as an energy source or other industrial material as bituminous or anthracite.


Properties:
color, texture, minerology, porosity

Sedimentary structures:
stratigraphy, cross-bedding, mudcracks, ripple marks

Principle of superposition
Unconformities

sedimentary rock uses