Sedimentary Rock

• Sedimentary Rocks are formed by pressure, heat, and “drying out”. Sediments do not necessarily have to be under tremendous pressure to become sedimentary rock (as seen in the lab).

Sedimentary Rock

Sedimentary Rock

• The Earths Crust is made up of solid bedrock. (Bedrock is solid rock that is connected continuously down into the Earth’s crust, rather than existing as separate pieces or

masses surrounded by loose materials

• Sedimentary Rock are by far the most common rock type in the upper crust

• Why is this?

Sedimentary Rock

• Rocks are broken down by weathering • http://www.learner.org/interactives/rockcycle

/change3.html• Sediment is transported by wind, water, or glaciers

to a new site, where it is deposited in layers. Over time, the sediments are buried and pressed together, or compacted. Eventually, the sediment is cemented together to form new rocks, know as sedimentary rock. This process takes millions of years

• Sedimentary Rock usually layered, that results from the consolidation or lithification of sediment, for example a clastic rock like sandstone or a chemical rock like rock salt, or an organic rock like coal (U8).

• Sedimentary Rock are either Marine (deposited in the ocean) or nonmarine

(deposited on the continents). If marine sedimentary rock are present, the area

must have been below sea level.

Sedimentary Rock

• Physical and Chemical processes work together to convert exposed bedrock

• Siliciclastic and Chemical

Sedimentary Rock

• Clastic – fragments of rocks and minerals that have been physically transported and deposited and then converted into rock

• Chemical – Direct precipitation of minerals from a solution. Only chemical sedimentary rocks are affected by chemical (vinegar/acid), all others are not affected, unless the acid is strong enough.

• Organic- Remains of plants and animals that have been converted into rock

Clastic Sedimentary Rock• Clastic Sedimentary Rock: a sedimentary rock made up of mostly of fragments derived from pre-existing rocks and

transported mechanically to their places of deposition. (U8)

• Clastic Sedimentary Rock are made up mostly of fragments, called clasts that are eroded from other rocks.

• Clay or Mud (Smallest 1/16 mm or smaller

• Sand (1/16 to 2 mm)

• Gravel (pebbles to boulders, bigger than 2mm)

Chemical Sedimentary

• Rocks consist of materials that have precipitated from the ocean water or lake water (Utah or Death Valley). Remember- Only chemical sedimentary rocks are affected by chemicals (U9)

• Precipitation: the process of forming solid mineral constituents from a solution by evaporation(U9)

Organic Sedimentary Rock

• a sedimentary rock consisting mainly of the remains of organisms (U10).

• Consists of the mineral calcite, a calcium carbonate mineral with the formula CaCO3

• Organic Sedimentary Rock forms when plants in swamps with rich vegetation die and are buried by the remains of later plants

Compaction and Cementation

Compaction and Cementation

Compaction: The reduction in bulk volume or thickness of fine-grained sediments owing to increasing weight of overlaying material that is continually being deposited (U11)

Cementation: The process by which sediments are converted into rock by the precipitation of a mineral “cement” among the grains of sediment (U11)

Lithification is the process of sediment that gradually becomes converted to solid rock. This is called lithified

Classification

• Classification, or the grouping or ordering of objects by similar features, is meant to make it easier for people to think about and discuss what they are investigating

• Distinguishing features of the rock samples will include things like the size of grains, the shape of the grains, what the grains are made of, if there are any visible fossils, and how the rock feels and even tastes.

Vocabulary

• Key Vocabulary: Sedimentary Rock, Compaction, Cementation, Bedrock, Clastic Sedimentary Rock, Clast, Precipitation Chemical Sedimentary Rock, And Organic Sedimentary Rock