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Sedimentary Rocks II Sedimentary Rock II
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Characteristics of clastic rocks Sedimentary Rock Types 5. Color: presence of key components (can be minor by volume)
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Characteristics of clastic rocks Sedimentary Rock Types 5. Color: BLACK: organic carbon, iron sulfide
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Characteristics of clastic rocks Sedimentary Rock Types 5. Color: BLACK: abundant dead organisms and stagnant water (not enough oxygen for decomposition)
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Characteristics of clastic rocks Sedimentary Rock Types 5. Color: BLACK: still water: swamp, lake, deep marine
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Characteristics of clastic rocks Sedimentary Rock Types 5. Color: Red or Brown: Iron Oxide high O 2 (continental)
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http://www.visitortips.com/images/gallery/destinations/usa/colorado/denver/fullsize/denver12.jpg
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Characteristics of clastic rocks Sedimentary Rock Types 6. Lithification: transformation of loose sediment into a rock
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Characteristics of clastic rocks Sedimentary Rock Types 6. Lithification: transformation of loose sediment into a rock compaction: degree (packing and fusion)
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http://www.grasp.ulg.ac.be/research/compaction/ Pre- Post- Compaction - packing
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http://www.grasp.ulg.ac.be/research/compaction/ Compaction - packing
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Compaction - grain fusion http://www.gly.uga.edu/railsback/PDFimage0208a.jpeg
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Characteristics of clastic rocks Sedimentary Rock Types 6. Lithification: transformation of loose sediment into a rock cementation: composition silica, calcite, hematite SiO 2 CaCO 3 FeO 2
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Quartz grains - Calcite cement
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http://faculty.gg.uwyo.edu/heller/Sed%20Strat%20Class/SedStratL1/Sedstrat%20gifs/sd1-p11.jpg Plagioclase grains - Calcite cement
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http://faculty.gg.uwyo.edu/heller/Sed%20Strat%20Class/SedStratL1/slideshow_1_16.htm q- quartz grains, o- quartz cement, c- calcite cement
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Characteristics of clastic rocks Sedimentary Rock Types 7. Texture: size, shape and arrangement of clasts.
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Characteristics of clastic rocks Sedimentary Rock Types Three components: grains: the larger particles (sand and larger)
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Characteristics of clastic rocks Sedimentary Rock Types Three components: grains: the larger particles (sand and larger) matrix: fine clastic particles deposited with grains
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Characteristics of clastic rocks Sedimentary Rock Types Three components: grains: the larger particles (sand and larger) matrix: fine clastic particles deposited with grains cement: chemical precipitate that fills voids after deposition
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Grains & CementGrains & Matrix Levin - Earth Through Time 7th
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Characteristics of clastic rocks Sedimentary Rock Types 8. Maturity: a measure of how long/far sediment was transported. two kinds
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Sedimentary Rock Types 8a. Textural Maturity: Immature large grain size, angular grains, poorly sorted intermediates small grain size, well rounded, well sorted Mature
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Characteristics of clastic rocks Sedimentary Rock Types 8b. Compositional Maturity: Immature - least stable rock fragments iron/magnesium minerals feldspars quartz Mature - most stable
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Sedimentary Rock Types most matureleast mature well roundedangular grains well sortedpoorly sorted fine grainedpebbles & sand quartzrock fragments Summary
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Characteristics of Clastic Rocks Sedimentary Rock Types 1.Grain size 2.Composition of grains 3.Sorting of grains 4.Shape of grains 5.Color of rock 6.Lithification process 7.Texture 8.Maturity a. textural b. compositional
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Environmental significance of sandstones Sedimentary Rock Types
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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 Environmental significance of sandstones
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Quartz sand http://www.gly.uga.edu/railsback/sands/260Micro900.jpeg
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Sedimentary Rock Types Quartz arenite : http://nessus.gunslingers.org/2003-09%20-%20North%20Carolina%20Beach%20and%20California%20Hiking/0047%20More%20Beach-half.jpg
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Sedimentary Rock Types Quartz arenite: tectonic setting Beach, far from the mountains Environmental significance of sandstones
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Sedimentary Rock Types 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 Environmental significance of sandstones
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Arkose http://smccd.net/accounts/hand/geology101/sedimentary/images/arkose2.jpg
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Sedimentary Rock Types Arkose: tectonic setting Physical weathering near granitic mountain Environmental significance of sandstones
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Sedimentary Rock Types Arkose
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Sedimentary Rock Types Wacke: matrix 30% of rock (dark minerals) little or no cement grains supported by matrix Environmental significance of sandstones
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Wacke http://www.smccd.net/accounts/hand/geology101/sedimentary/images/greywacke1.jpg
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Sedimentary Rock Types Wacke: tectonic setting Rapid uplift near continent margin Environmental significance of sandstones
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Episodes of deposition Turbidites
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Episodes of deposition Turbidites
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One Turbidite
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Turbidites http://www.kickkleverlaan.com/ratab%20red.jpg
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Turbidites & Deep Marine Shales
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Sedimentary Rock Types Lithic sandstone: quartz, mica, chert, rock frag. little feldspar 15% matrix or less, rest cement intermediate rounding & sorting Environmental significance of sandstones
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Lithic sand (Mekong river) http://staff.aist.go.jp/sudo-gsj/sand/english/D-2444.html
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Sedimentary Rock Types Lithic sandstone: tectonic setting delta on the edge of a coastal plain Environmental significance of sandstones
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Sedimentary Rock Types Environmental significance of sandstones Lithic sand
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Environmental significance of sandstones Sedimentary Rock Types Beach far from Mt Continental arid Deep Marine Mature River
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