Geology: Sedimentary Rocks

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  1. Describe the abundance of sedimentary rock and note why they are important?
    Sedimentary Rocks contain evidence of past environments.

    Coal is a sedimentary rock that provides an economic importance.
  2. List/describe the processes involved in diagenesis.
    Sediments are deposited and buried at shallow depths in the Earth's crust.

    • Lithification occurs:
    • Compaction - squeezes out water
    • Cementation - Precipitation or addition of new minerals cements sediment particles
  3. List/briefly describe the 3 general compositional types of sedimentary rocks.
    Siliciclastic: composed of mineral particles formed by the weathering of silicate rocks.

    Chemical: formed by the precipitation of dissolved material of chemical weathering

    Biochemical: formed from mineral precipitation by organisms
  4. List minerals commonly found in sedimentary rocks.
    • Quartz
    • Clay Minerals
    • Feldspars
    • Micas
    • Shale(most common - made from compacted mud)
  5. What is the texture of siliciclastic rocks and what texture features are used to identify these rocks?  Give examples.
    • Grain Sizes
    • Gravel-sized
    • Sand-sized
    • Clay-sized
    • Microcrystallize
    • Crystalline

    • Grain Shape
    • Well Rounded
    • Angular
    • Rounded

    • Grain Sorting
    • Well Sorted
    • Moderately Sorted
    • Poorly Sorted
  6. List/briefly describe the siliciclastic rocks we covered.
  7. How does the velocity of wind/water currents affect sediment deposition?
  8. What is the most common sedimentary rock?
  9. Explain how chemical sedimentary rocks are formed.
    Formed by the precipitation of dissolved material of chemical weathering
  10. Give examples of chemical rocks and note minerals present in each.
    • Limestone - Calcite
    • Rock Gypsum - Gypsum
    • Rock Salt - Halite
    • Chert - Quartz
    • Dolostone - Dolomite
  11. Explain how biochemical sedimentary rocks are formed.
    Formed from mineral precipitation by organisms
  12. Give examples of biochemical rocks and note minerals present in each.
    • Limestone - Calcite
    • Chert - Microcrystalline Quartz
  13. List/ describe several specific sedimentary environments and note the specific rocks formed in each.
    • Continental
    • Built around rivers, lakes, deserts, glacial deposits, and alluvial fans
    • Rocks:

    • Shoreline
    • Deltas, Beaches, Swamps, Bays
    • Rocks:

    • Marine
    • Ocean, Reefs
    • Rocks:
  14. Give examples of how can we use sedimentary rocks to deduce past environmental conditions.
  15. List, briefly describe, and discuss the importance of sedimentary structures (i.e. how can they be used to deduce transport medium or environmental conditions).
    Cross-bedding - beds deposited by wind or water layered down at an angle

    Graded-bedding - deep-sea sediments deposited by turbidity currents with particle sizes becoming finer upwards

    Ripples - small ridges of sand or silt formed by water or wind currents

    Mud Cracks - evaporated water leaving behind solid mud

    • Strata/beds(layers)
    • Fossils
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Geology: Sedimentary Rocks
2013-11-04 01:02:46
Geology Sedimentary Rocks

Geology Exam for Sedimentary Rocks
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