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Sedimentary Rocks II Sedimentary Rock II. Characteristics of clastic rocks Sedimentary Rock Types 5. Color: presence of key components (can be minor by.

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Presentation on theme: "Sedimentary Rocks II Sedimentary Rock II. Characteristics of clastic rocks Sedimentary Rock Types 5. Color: presence of key components (can be minor by."— Presentation transcript:

1 Sedimentary Rocks II Sedimentary Rock II

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

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

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

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

6 Characteristics of clastic rocks Sedimentary Rock Types 5. Color: Red or Brown: Iron Oxide high O 2 (continental)

7

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

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

10 Pre- Post- Compaction - packing

11 Compaction - packing

12 Compaction - grain fusion

13 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

14 Quartz grains - Calcite cement

15 Plagioclase grains - Calcite cement

16 q- quartz grains, o- quartz cement, c- calcite cement

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

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

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

20 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

21 Grains & CementGrains & Matrix Levin - Earth Through Time 7th

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

25 Sedimentary Rock Types most matureleast mature well roundedangular grains well sortedpoorly sorted fine grainedpebbles & sand quartzrock fragments Summary

26 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

27 Environmental significance of sandstones Sedimentary Rock Types

28 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

29 Quartz sand

30 Sedimentary Rock Types Quartz arenite :

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

32 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

33 Arkose

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

35 Sedimentary Rock Types Arkose

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

37 Wacke

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

39 Episodes of deposition Turbidites

40 Episodes of deposition Turbidites

41 One Turbidite

42 Turbidites

43 Turbidites & Deep Marine Shales

44 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

45 Lithic sand (Mekong river)

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

47 Sedimentary Rock Types Environmental significance of sandstones Lithic sand

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


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