02. Sedimentary Rocks

Sedimentary rock is rock that forms from sediment that accumulates and transforms into rock on Earth’s surface. There are three step to sedimentary rock formation:

1. Deposition (Sedimentation)

2. Compaction

3. Cementation

Deposition

- Sediments are small particles of minerals and organic matter. They form when older rocks are weathered (broken down) by different environmental forces such as wind and water.

- Over time, sediment is deposited on the ground or at the bottom of lakes and oceans. Sediment accumulates and forms layers. This process is known as deposition or sedimentation.

Compaction

- Over time, the layer of sediment is covered by more sediment. More layers pile up and press down on the lower layers.

- The weight and pressure of higher layers compresses or compacts the sediment particles in lower layers. This process is called compaction.

Cementation

- The weight of the top layers presses water out of the lowest layers of sediment. Minerals move into tiny spaces where the water once was. The minerals act like glue or cement and bind the sediments together. This

process is called cementation.

Important Considerations

- A cross section of a sedimentary rock show layers. We call these layers strata. The layers at the bottom are older than layers at the top.

- The particles in a layer of sedimentary rock can tell us what the environment was like at the time those sediments were deposited.

- Fossils can form in layers of sedimentary rock. Fossils found in older layers of rock are older than fossils found in younger layers of rock.

Activity:

Having read the above information about how Sedimentary rocks are formed, complete the Interactive Notebook (INB) Activity; cutting out the diagram, sticking it in, writing the descriptions under the flaps and then colouring the front of the diagrams.

Activity: Use the instruction sheet and the resources available to make your own sedimentary rocks.

Assessment: Complete the Sedimentary Rock Formation - Mini Assessment

Activity:

Using the lenses, observe your sedimentary rocks that you prepared last lesson. Write descriptions for these that you can add to photographs in Google Slides Presentation.

Carefully, look at the samples of sedimentary rock provided. Choose the one that most closely resembles each of your samples, take a photo and add the photo and its name to your Google Slide presentation.