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Sediments and Sedimentary Rocks

Sediments and Sedimentary Rocks. Sediments and Sedimentary Rocks. And. Pressure. Cementation. Erosion. Sedimentary Rocks. Sediment. Erosion. Heat. Erosion. Pressure. Heat and Pressure. Igneous Rocks. Metamorphic Rocks. Cooling. Heat. Magma. Sediments ( soft )

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Sediments and Sedimentary Rocks

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  1. SedimentsandSedimentary Rocks

  2. Sediments and Sedimentary Rocks And Pressure Cementation Erosion SedimentaryRocks Sediment Erosion Heat Erosion Pressure Heat and Pressure Igneous Rocks MetamorphicRocks Cooling Heat Magma

  3. Sediments (soft) Material (such as gravel, sand, mud, and lime) that is transported by wind, water, ice, or gravity; Material that is precipitated from solution; Deposits of organic origin (such as coal and coral reefs). Sedimentary Rock (hard) Rock formed by the accumulation and consolidation of sediment.

  4. Sediments - unconsolidated particles created by 1. The weathering of rock 2. The secretions of organisms or decomposition of organic matter 3. Chemical precipitation

  5. Sedimentary Rocks • Composed of lithified sediments • by compaction • by cementation Two (Textures) - clastic (detrital) - nonclastic

  6. Types of Sediments Clastic Nonclastic 1. Biochemical 2. Chemical

  7. Igneous Rocks Sedimentary Rocks 1. Phaneritic 2 .Aphanitic * Glassy * Vesicular 1. Clastic 2. Nonclastic * Biochemical * Chemical

  8. Types of Sediments • 1. Clastic – broken fragments of rock produced by weathering. Range in size from largest boulder to smallest clay particle. Classified according to size. Found everywhere on the Earth.

  9. Clastic Texture Texture - Size, shape, and distribution of particles that collectively make up a rock • Size • Rounding • Sorting

  10. Clastic Sediment Size

  11. Clastic Texture • Roundness – the shape of sediment grains. • Related to the distance a sediment has been transported. Sphericity - how close to a spherical shape a grain is or will be.

  12. Roundness / Sphericity of Sediments

  13. Size Rounding Sphericity Sorting

  14. Clastic Sediments Sorting • Sorting – separation of sediments by grain size and density. Poorly sorted – sediment with a wide range of grain sizes. Well sorted – sediment with a small range of grain sizes.

  15. Sorting of Sediments

  16. Sorting - a function of transported 1. Water 2. Wind 3. Glaciers

  17. Texture and Transport Distance • In general, as transport distance increases, rounding and sorting increase. Examples: Breccia – cemented close to source Conglomerate – transported then cemented

  18. Depositional Environments of Sedimentary Rocks Smaller….Rounder…..Better Sorted Clastic Sedimentary Rocks Nonclastic Sedimentary Rocks Basin Source Downstream Beach Offshore (Playa Lake) Breccia Conglomerate Arkose Sandstone Lithic Sandstone Quartz Sandstone Halite, Gypsum, Chert(Evaporites) Shale Siltstone Coal Reef Coquina Swamp Limestone

  19. Sorting by Water Graded Beds

  20. Graded Beds Fining up

  21. Sorting by Wind

  22. Cross Bedding – water or wind

  23. Sorting by Glaciers

  24. Clast Size / Rock Name Relationship Large Clasts Small Clasts

  25. Breccia - Formed at the source

  26. Conglomerate – Formed near the source

  27. Sandstone – Down stream to just off shore

  28. Tidal Flat Deposit Stream Deposit

  29. Off-Shore Environments

  30. Strata Stratum Stratigraphy Stratigraphic • relating to layered • sedimentary rocks

  31. Bedding – Layering or stratification in sedimentary rock

  32. Types of Sediments • 2. Biochemical – composed of remains of plants or animals.

  33. Biogenic Sediments Terestrial Sediments - mainly plant matter Marine Sediments - mainly carbonates Corals - Large components of reefs. Bivalves, Gastropods, Foraminifers - Whole or partial skeletons form sand and gravels. Aglae, Crinoids, Echinoderms, Bryozoans - disintergrate to form some sand particles and lime mud. Diatoms, Radiolaria – Bedded chert SiO2

  34. Coral (carbonate)

  35. Foramanifera

  36. Diatoms

  37. Types of Sediments • 3. Chemical – formed by minerals precipitating from solution. Inorganic process, no biological activity involved.

  38. Bonneville Salt Flats

  39. Chemical Sediments 1. Terestrial - Evaporites: Gypsum - CaSO4 . H2O Anhydrite - CaSO4 Halite - NaCl 2. Marine - Carbonates - CaCO3 (Whitings)

  40. Sedimentary Rocks Clastic Rock – composed of fragments of preexisting rocks. Nonclastic Rock – composed of chemical precipitates or biogenic matter.

  41. Ripple Marks

  42. Mud Cracks

  43. Burrows

  44. Depositional Environments Where sedimentary rock live!

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