Sedimentary Rock Notes

Weathering• Weathering is a process that

breaks down preexisting rocks into sediment. – Caused by• Wind• Water• Ice• Sunlight• Gravity

Sediment

• Rock and mineral fragments (pieces) are called sediment

Erosion

• Through the process of erosion, sediment is moved from one place to another.

Deposition

• After weathering and erosion occur, sediment is “dropped” or deposited in layers.– This is called

deposition.

Sedimentary Rock Formation• Sedimentary rock is formed when sediment

(created by weathering, moved by erosion, and deposited in layers) is compacted and cemented together.– Compact: Closely packed together– Cement: To bind together

Strata

• The most noticeable feature of sedimentary rock is its strata (or layers).

Sedimentary Rock Classification

• Sedimentary rock is classified by the way it forms– 3 main types:• Clastic• Chemical• Organic

Clastic Sedimentary Rock

• Clastic sedimentary rock forms when rock or mineral fragments, called clasts, stick together.

Chemical Sedimentary Rock

• Chemical sedimentary rock forms when minerals crystallize out of a solution to become rock.– Example: Rain water

dissolves some rock material. This material crystallizes and forms minerals that make up chemical sedimentary rock

Organic Sedimentary Rock

• Organic sedimentary rock forms from the remains of once-living plants and animals.

Sedimentary Rock Structures

Stratification: The process in which sedimentary rocks are arranged in layers.

Ripple marks: Marks in rock made by water and wind

Mud cracks: Form when fine-grained sediments at the bottom of a shallow body of water are exposed to the air and dry out.

Indicate the location of an ancient lake, stream, or ocean shoreline

Preexisting Rock

Sedimentary Rock

Sediment

Weathering

Erosion

Compaction & Cementation

Deposition