1. CHAPTER 6.3
SEDIMENTARY ROCKS

2. SEDIMENTARY ROCKS
95% OF EARTHS CRUST IS IGNEOUS ROCK, AND 4-5% IS SEDIMENTARY AND METAMORPHIC ROCK
SEDIMENTS – ANY SUBSTANCE THAT SETTLES OUT OF A FLUID
Created by weathering and erosion
WEATHERING – THE PROCESS BY WHICH ROCKS ARE BROKEN UP INTO FRAGMENTS
MECHANICAL, CHEMICAL AND BIOLOGICAL
EROSION – THE REMOVAL AND TRANSPORT OF EARTH MATERIALS BY NATURAL AGENTS
LITHIFICATION – PROCESS BY WHICH MATERIALS BECOME ROCK

5. ORIGIN OF SEDIMENTS:
1. CLASTIC – ROCK FRAGMENTS FORMED BY WEATHERING/EROSION OF EXISTING ROCK
DEFINED BY SIZE -
SMALLEST TO LARGEST
CLAY, SILT, SAND, GRAVEL
Clastic sediments are often sorted by water action before pressure and mineral cements turn them into rock.

6. LITHIFICATION OF CLASTICS:
a.) CEMENTATION DISSOLVED MINERALS THAT BIND PARTICLES TOGETHER
SILICA – FROM QUARTZ. GRAY OR WHITE
LIME – FROM CALCITE. GRAY OR WHITE
IRON – VARIOUS IRON MINERALS RED, BROWN, YELLOW
b.) COMPACTION – PRESSURE OF OVERLYING MATERIALS LITHIFY DEPOSITS

7. 1. A river moves sediment into a lake.
2. Particles are sorted by size. The largest gravels are the first to be deposited, followed by sands, and then silt and clay.
Sands and Gravels
Sands
Silt and Clay
3. Over time, the sediments are buried, compacted, and may be cemented.
Conglomerate
Sandstone
Shale

9. CLASTIC SEDIMENTARY ROCKS:
CONGLOMERATE – CEMENTED MIXTURE OF ALL SIZES OF CLASTIC MATERIALS. LARGEST PEBBLES (QUARTZ)
SANDSTONE – CEMENTED QUARTZ / FELDSPAR GRAINS
SILTSTONE – SILT SIZED PARTICLES
SHALE – COMPACTED SILT OR CLAY. OFTEN OCCUR IN FLAT SHEET LIKE LAYERS.

10. SANDSTONE
CONGLOMERATE

11. SILTSTONE
SHALE

12. 2. CHEMICAL SEDIMENTARY ROCKS – SEDIMENTS THAT FORM FROM EVAPORATION OR PRECIPITATES
LIMESTONE – CHEMICAL DEPOSITION OF CALCITE
ROCK SALT – EVAPORATIVE DEPOSITION OF HALITE
ROCK GYPSUM – EVAPORATIVE DEPOSITION OF GYPSUM

13. LIMESTONE
ROCK GYPSUM
ROCK SALT

14. 3. ORGANIC – SEDIMENTS FORMED FROM THE REMAINS OF PLANTS AND ANIMALS
COQUINA – LIMESTONE FORMED BY THE CALCUIM REMAINS OF MARINE ANIMALS
SHELL LIMESTONE – SHELLS CEMENTED BY LIME OR CLAY MATRIX
BITUMINOUS COAL – COMPACTION OF PLANT MATERIAL

15. COQUINA

16. SHELL LIMESTONE

17. BITUMINOUS COAL

18. SEDIMENTARY ROCK FEATURES:
STRATIFICATION – THE DEPOSITION OF SEDIMENTS INTO IN BEDS GIVES A LAYERED APPEARANCE

20. BEDDING PLANE – THE LINE THAT SEPARATES ROCK LAYERS
BEDDING PLANE – THE LINE THAT SEPARATES ROCK LAYERS. ORIGINALLY DEPOSITED IN NEARLY HORIZONTAL POSITION.

21. CROSS BEDDING – BEDS ARE DEPOSITED IN INCLINED LAYERS
CROSS BEDDING – BEDS ARE DEPOSITED IN INCLINED LAYERS. COMMON IN WIND OR DELTAIC DEPOSITS.

24. FOSSILS – THE REMAINS OR IMPRESSIONS OF PLANTS OR ANIMALS IN ROCK

25. RIPPLE MARKS – FEATURES FORMED BY THE ACTION OF WIND OR WATER CURRENTS.
MUD CRACKS – DEVELOP WHEN DEPOSITS WITH HIGH % OF CLAY DRY AND CONTRACT.
CONCRETION – ROUND OR EGG SHAPED BODIES FOUND IN LIMESTONE OR SHALEBEDS.