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Sedimentary Rocks II

Sedimentary Rock II. Sedimentary Rocks II. Sedimentary Rock Types. Characteristics of clastic rocks. 5. Color : • presence of key components (can be minor by volume). Sedimentary Rock Types. Characteristics of clastic rocks. 5. Color : • BLACK : organic carbon,

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Sedimentary Rocks II

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  1. Sedimentary Rock II Sedimentary Rocks II

  2. Sedimentary Rock Types Characteristics of clastic rocks 5. Color: • presence of key components (can be minor by volume)

  3. Sedimentary Rock Types Characteristics of clastic rocks 5. Color: •BLACK: organic carbon, iron sulfide

  4. Sedimentary Rock Types Characteristics of clastic rocks 5. Color: •BLACK: abundant dead organisms and stagnant water (not enough oxygen for decomposition)

  5. Sedimentary Rock Types Characteristics of clastic rocks 5. Color: •BLACK: still water: swamp, lake, deep marine

  6. Sedimentary Rock Types Characteristics of clastic rocks 5. Color: Red or Brown: Iron Oxide high O2 (continental)

  7. http://www.visitortips.com/images/gallery/destinations/usa/colorado/denver/fullsize/denver12.jpghttp://www.visitortips.com/images/gallery/destinations/usa/colorado/denver/fullsize/denver12.jpg

  8. Sedimentary Rock Types Characteristics of clastic rocks 6. Lithification: • transformation of loose sediment into a rock

  9. Sedimentary Rock Types Characteristics of clastic rocks 6. Lithification: • transformation of loose sediment into a rock •compaction: degree (packing and fusion)

  10. Pre- Post- http://www.grasp.ulg.ac.be/research/compaction/ Compaction - packing

  11. http://www.grasp.ulg.ac.be/research/compaction/ Compaction - packing

  12. http://www.gly.uga.edu/railsback/PDFimage0208a.jpeg Compaction - grain fusion

  13. Sedimentary Rock Types Characteristics of clastic rocks 6. Lithification: • transformation of loose sediment into a rock •cementation: composition silica, calcite, hematite SiO2 CaCO3 FeO2

  14. Quartz grains - Calcite cement

  15. http://faculty.gg.uwyo.edu/heller/Sed%20Strat%20Class/SedStratL1/Sedstrat%20gifs/sd1-p11.jpghttp://faculty.gg.uwyo.edu/heller/Sed%20Strat%20Class/SedStratL1/Sedstrat%20gifs/sd1-p11.jpg Plagioclase grains - Calcite cement

  16. http://faculty.gg.uwyo.edu/heller/Sed%20Strat%20Class/SedStratL1/slideshow_1_16.htmhttp://faculty.gg.uwyo.edu/heller/Sed%20Strat%20Class/SedStratL1/slideshow_1_16.htm q-quartz grains,o-quartz cement,c-calcite cement

  17. Sedimentary Rock Types Characteristics of clastic rocks 7. Texture: size, shape and arrangement of clasts.

  18. Sedimentary Rock Types Characteristics of clastic rocks Three components: •grains: the larger particles (sand and larger)

  19. Sedimentary Rock Types Characteristics of clastic rocks Three components: •grains: the larger particles (sand and larger) •matrix: fine clastic particles deposited with grains

  20. Sedimentary Rock Types Characteristics of clastic rocks Three components: •grains: the larger particles (sand and larger) •matrix: fine clastic particles deposited with grains •cement: chemical precipitate that fills voids after deposition

  21. Levin - Earth Through Time 7th Grains & Cement Grains & Matrix

  22. Sedimentary Rock Types Characteristics of clastic rocks 8. Maturity: a measure of how long/far sediment was transported. two kinds

  23. Sedimentary Rock Types 8a. Textural Maturity: Immature • large grain size, angular grains, poorly sorted • intermediates • small grain size, well rounded, well sorted Mature

  24. Sedimentary Rock Types Characteristics of clastic rocks 8b. Compositional Maturity: Immature - least stable • rock fragments • iron/magnesium minerals • feldspars • quartz Mature - most stable

  25. Sedimentary Rock Types Summary

  26. Sedimentary Rock Types Characteristics of Clastic Rocks Grain size Composition of grains Sorting of grains Shape of grains Color of rock Lithification process Texture Maturity a. textural b. compositional

  27. Sedimentary Rock Types Environmental significance of sandstones

  28. Sedimentary Rock Types Environmental significance of sandstones 1. Quartz arenite: • dominance of quartz • little or no feldspar, mica, or matrix • grains well rounded, well sorted • calcite or silica cement • wide spread thin sand beds

  29. http://www.gly.uga.edu/railsback/sands/260Micro900.jpeg Quartz sand

  30. Sedimentary Rock Types Quartz arenite : http://nessus.gunslingers.org/2003-09%20-%20North%20Carolina%20Beach%20and%20California%20Hiking/0047%20More%20Beach-half.jpg

  31. Sedimentary Rock Types Environmental significance of sandstones Quartz arenite: tectonic setting • Beach, far from the mountains

  32. Sedimentary Rock Types Environmental significance of sandstones Arkose: (feldspathic wacke) • contain 25% or more feldspar (pink) • quartz most abundant (angular) • calcite, iron oxide cement, or clay matrix • granitic source • coarse sand, moderately well sorted

  33. http://smccd.net/accounts/hand/geology101/sedimentary/images/arkose2.jpghttp://smccd.net/accounts/hand/geology101/sedimentary/images/arkose2.jpg Arkose

  34. Sedimentary Rock Types Environmental significance of sandstones Arkose: tectonic setting • Physical weathering near granitic mountain

  35. Sedimentary Rock Types Arkose

  36. Sedimentary Rock Types Environmental significance of sandstones Wacke: •matrix 30% of rock (dark minerals) •little or no cement •grains supported by matrix

  37. http://www.smccd.net/accounts/hand/geology101/sedimentary/images/greywacke1.jpghttp://www.smccd.net/accounts/hand/geology101/sedimentary/images/greywacke1.jpg Wacke

  38. Sedimentary Rock Types Environmental significance of sandstones Wacke: tectonic setting • Rapid uplift near continent margin

  39. Episodes of deposition Turbidites

  40. Episodes of deposition Turbidites

  41. One Turbidite

  42. http://www.kickkleverlaan.com/ratab%20red.jpg Turbidites

  43. Turbidites & Deep Marine Shales

  44. Sedimentary Rock Types Environmental significance of sandstones Lithic sandstone: • quartz, mica, chert, rock frag. • little feldspar • 15% matrix or less, rest cement • intermediate rounding & sorting

  45. Lithic sand (Mekong river) http://staff.aist.go.jp/sudo-gsj/sand/english/D-2444.html

  46. Sedimentary Rock Types Environmental significance of sandstones Lithic sandstone: tectonic setting •delta on the edge of a coastal plain

  47. Sedimentary Rock Types Environmental significance of sandstones Lithic sand

  48. Sedimentary Rock Types Environmental significance of sandstones Beach far from Mt Continental arid Deep Marine Mature River

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