How are Sedimentary rocks formed?

Description of Sedimentary Rocks

1. How are sedimentary rocks formed?

2. Common sedimentary rocks include sandstone, limestone, and shale. 2

3. The formation of sedimentary rocks begins with the accumulation and consolidation of sediment or of rock fragments. 3

4. Sedimentary rocks are made up of fragments of other rocks. The deposition of these sediments in layers, in lakes or seas, takes place over millions of years. The deposited sediments are transformed into compact, cohesive rocks. 4

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6. Rocks are fragmented by: Weathering -Rocks at the surface of the Earth are broken up by the action of atmospheric phenomena (changes in temperature, rain, acid rain), or by the activities of plants and animals. Erosion -These broken fragments of rocks are swept away by running water, glaciers, waves or wind. 6

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9. SEDIMENTARY ROCKS These rocks often start as sediments carried in rivers and deposited in lakes and oceans. When buried, the sediments lose water and become cemented to form rock. 9

10. How are fossils formed? Sedimentary rocks sometimes contain remains of living things that lived millions of years ago. These remains are called fossils . Fossils become part of the rocks during the processes of compaction and cementation of sediments. Fossils provide invaluable information about the history of life on Earth. 10

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13. Rock fragments join to form rock by two processes: COMPACTION CEMENTATION 13

14. 14 Compaction The weight of successive layers of sediment compacts the sediments more. This pressure reduces the spaces between the fragments and squeezes out the water. As a result, salt crystals are formed ..

15. 15 Cementation The rock fragments are stuck together with the salt crystal which formed when the water was eliminated. Each layer of sediments is transformed into a layer of sedimentary rock. This layer is called a stratum (plural: strata).

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17. explain how sedimentary rocks are formed explain how fossils are formed RECITATION talk about the ways how rocks are fragmented 17

18. I llustrate sedimentary rocks, weathering and erosion H ave you witnessed a rock erosion in their country or community? Explain what natural phenomena caused the erosion M ake a reflection or short essay on how important are sedimentary rocks in our everyday living particularly the fossil fuel or create an appreciation slogan for Mother Nature 18