Sedimentary rocks 20122013

Sedimentary RocksSedimentary RocksS6E5. Students will investigate the scientific view of how the earth’s surface is formed. c. Classify rocks by their process of formation. Enduring Understanding: Rocks are grouped based on how they formed and their mineral composition.

DirectionsDirections1.1. ReadRead over the note taking organizer. over the note taking organizer.

2.2. Read each slide.Read each slide.

3.3. Next fill in the blanks with the Next fill in the blanks with the

underlinedunderlined words. words. Some slides Some slides are just used for information are just used for information purposes. purposes.

Intro to Sedimentary Rocks• Produced from weathering products of pre-existing rocks or accumulated biological matter

– Detrital (clastic) rocks produced from rock fragments– Chemical rocks produced by precipitation of dissolved ions in water– Organic rocks produced by accumulation of biological debris, such as in swamps or bogs

• Sedimentary rock types and sedimentary structures within the rocks give clues to past environments

• Fossils in sedimentary rocks give clues to the history of life• Important resources (coal, oil) are found in sedimentary rocks

4. 3 Notes: Sedimentary Rocks4. 3 Notes: Sedimentary Rocks

http://www.fi.edu/fellows/payton/rocks/create/sediment.htm

Sedimentary rocks are layers of sediment cemented together. The sedimentary process begins with igneous, sedimentary and metamorphic

rocks weathered which is the breaking down

of rocks followed by erosion the movement from the Earth's surface by natural processes such as wind or water flow, through the act of

transportation. The transfer of sediments (soil particles) from one place to another followed

by deposition the layering after layering of

the sediment. Then Compaction occurs after the sediments have been deposited.

Cementation the final process acts as glue or cement to bind the sediments together forming sedimentary rocks.

From Sediment to Sedimentary Rock• Transportation

– Movement of sediment away from its source, typically by water, wind, or ice

– Rounding of particles occurs due to abrasion during transport

– Sorting occurs as sediment is separated according to grain size by transport agents, especially running water

– Sediment size decreases with increased transport distance

Origin Origin (Formed where) Comprise Comprise 75%75% of the of the Earth’s surfaceEarth’s surface Formed when sediments become Formed when sediments become

compactedcompacted and and cementedcemented together together Usually has Usually has layerslayers called called stratastrata

The highest layer has the least pressure.

The lowest layer has the most pressure.

CompactionCompactionWhat does What does

compaction mean?compaction mean?– Layer upon layer of Layer upon layer of

sediment builds sediment builds up up and the and the pressure pressure from the upper from the upper layers pushes down layers pushes down on the lower layers.on the lower layers.

– Only Only SMALL SMALL sediments sediments will stick will stick together to form rocktogether to form rock

The highest layer has the

least pressure.

The lowest layer has the

most pressure.

CementationCementation

What does it mean? (Process)What does it mean? (Process)– WaterWater soaks through soil and rock. The soaks through soil and rock. The

water water dissolves minerals dissolves minerals in soil and in soil and rock. rock.

– The The solutionsolution of of mineralsminerals and and waterwater moves between the sediments. moves between the sediments.

– The sediments The sediments stickstick together when the together when the minerals crystallize.minerals crystallize.

– Common with Common with LARGELARGE sediments sediments

Classification Classification (Grouping) Sedimentary rocks are classified in 3 Sedimentary rocks are classified in 3

ways… (By the way they are ways… (By the way they are formedformed))

1. 1. Detrital Detrital ClasticClastic Sedimentary Rocks Sedimentary Rocks

2. 2. ChemicalChemical Sedimentary Rocks Sedimentary Rocks

3. 3. OrganicOrganic Sedimentary Rocks Sedimentary Rocks

It’s by the way they are formed!!!

1. ClasticClastic Sedimentary Rock Sedimentary Rock

Made from Made from broken fragments of broken fragments of other rocks.other rocks.– EX: ConglomerateConglomerate = large/ = large/roundround

fragmentsfragments

– EX: BrecciaBreccia = large/ = large/sharpsharp fragments fragments

Breccia Conglomerate

Clastic Rock FactsClastic Rock FactsClastic – made of fragments of rock cemented together with calcite or quartz

Breccia is a term most often used for clastic sedimentary rocks that are composed of large angular fragments (over two millimeters in diameter).

The spaces between the large angular fragments can be filled with a matrix of smaller particles or a mineral cement that binds the rock together.

2. Chemical2. Chemical Sedimentary Sedimentary RockRock

Formed from Formed from minerals crystallizingminerals crystallizing out of a solution out of a solution

The solution is made of The solution is made of mineralsminerals and and water.water.

Halite (Rock Salt)

Chemical Rock FactsChemical Rock FactsChemical sedimentary – minerals crystallize out of solution to become rock

Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters.

It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris.

3. Organic3. Organic Sedimentary Rock Sedimentary Rock

Rocks formed Rocks formed from once-living from once-living ((organicorganic) things.) things.

EX: Organic

Limestone

Ocean animals called coral create huge deposits of limestone. As they die, their skeletons collect on the ocean floor.

Organic Rock FactsOrganic Rock FactsOrganic sedimentary – remains of plants and animals

Coal is an organic sedimentary rock that forms from the accumulation and preservation of plant materials, usually in a swamp environment. 

Coal is a combustible rock and along with oil and natural gas it is one of the three most important fossil fuels. 

StratificationStratification The process in which sedimentary The process in which sedimentary

rocks are arranged in rocks are arranged in layerslayers. .

Separating each strata are bedding planes.

Bedding Planes are flat surfaces along which the rock tends to break.

Caused by changes in grain size.May also occur after pauses in deposition.