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Aim: How do sedimentary rocks form?

Aim: How do sedimentary rocks form?. Do Now:. Predict how each sediment will settle in a jar full of water: Sand Pebbles Rocks Soil. A. Sediments in water deposit with the largest first, then the smallest. Rocks (heaviest settle on bottom) Pebbles Sand may fill in the gaps

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Aim: How do sedimentary rocks form?

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  1. Aim: How do sedimentary rocks form?

  2. Do Now: • Predict how each sediment will settle in a jar full of water: • Sand • Pebbles • Rocks • Soil

  3. A. Sediments in water deposit with the largest first, then the smallest • Rocks (heaviest settle on bottom) • Pebbles • Sand may fill in the gaps • Soil (smallest lays on top, may also float in suspension)

  4. Sediment sizes can be found on this ESRT chart:

  5. Definitions: • Sediment • Weathering • Erosion • Deposition • Compaction • Cementation • Clastic • Fossil

  6. B. What are sedimentary rocks made from? • Sedimentary rocks form from pieces of existing rock that have been worn away (weathered), carried to new place (erosion) and deposited there (deposition). • These pieces of rock are called sediments. • Water, ice, gravity, and wind are the agents of erosion. • Most sedimentary rocks form in water.

  7. C. How do deposited sediments form rocks? • Sediments settle loosely. • More sediments settle on top and press them together (compaction) • Over years, more layers of sediments settle and get compacted.

  8. In sedimentary rock formations, where would you find the oldest layers? • Older layers form on the bottom unless they have been uplifted or tilted by movement of the crust!

  9. D. What holds the sediments together? • Minerals in the sediments dissolve in water and seep into the spaces between the sediments. • The minerals form a “glue” that hold the sediments together. (cementation). Watch sedimentary rocks form

  10. Trace the path of an igneous rock to a sedimentary rock. What other kinds of rock can become sedimentary? UPLIFT means that a rock must be pushed up toward the surface where weathering takes place in order to become a sediment

  11. Aim: What are the 3 ways sedimentary rocks form?

  12. E. Three processes that form sedimentary rocks: • Clastic – rock fragments held togetherExamples: shale, sandstone, conglomerate • Organic (bioclastic) – remains of plants and animals deposited in thick layers, can contain fossilsExamples: Coal, limestone (fossil or coquina) • Chemical – minerals dissolved in water re-crystallize into rocks when water evaporatesExamples: halite (rock salt), rock gypsum, chalky limestone

  13. F. Clastic Examples – sediments with different sizes (usually more than 1 mineral) Conglomerate -big rounded sediments Breccia – big sharp sediments Sandstone – sand sized sediments Siltstone - silt Shale –mud, clay

  14. G. Organic Examples (bioclastic) : Limestone • It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris. Always forms in water. • Only 1 mineral limestone Fossil limestone coquina

  15. G. Organic Examples: Coal Coal is formed by plant debris piling up in water. http://www.classzone.com/books/earth_science/terc/content/visualizations/es0701/es0701page01.cfm?chapter_no=07

  16. H. Chemical: Crystaline • Formed from precipitation or evaporation in water • Only 1 mineral Rock Salt – evaporite, sedimentary form of mineral halite Rock Gypsum – precipitate form of mineral gypsum Dolostone – precipitate form of mineral dolomite

  17. I. Sedimentary Rocks: • Are the most abundant kind of rock on the outer surface (75%+). • Trap a history of the earth in the layers of rock. (life forms, climate and natural events)

  18. J. Grand Canyon • http://www.youtube.com/watch?v=XckLEPTmKjA&feature=related

  19. Describe some characteristics a sedimentary rock might have: • Layers • Sand particles • Pebbles –round or jagged • Fossils • Crystals

  20. Label the sedimentary rock as organic, clastic or chemical.

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