SEDIMENTARY ROCKS

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CHAPTER 6.3

• SEDIMENTARY ROCKS

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• 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

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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.
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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
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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.
3. Over time, the sediments are buried,
compacted, and may be cemented.
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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.
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SANDSTONE
CONGLOMERATE
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SILTSTONE
SHALE
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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
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LIMESTONE
ROCK GYPSUM
ROCK SALT
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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
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COQUINA
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SHELL LIMESTONE
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BITUMINOUS COAL
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SEDIMENTARY ROCK FEATURES STRATIFICATION THE
DEPOSITION OF SEDIMENTS INTO IN BEDS GIVES A
LAYERED APPEARANCE
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BEDDING PLANE THE LINE THAT SEPARATES ROCK
LAYERS. ORIGINALLY DEPOSITED IN NEARLY
HORIZONTAL POSITION.
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CROSS BEDDING BEDS ARE DEPOSITED IN INCLINED
LAYERS. COMMON IN WIND OR DELTAIC DEPOSITS.
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FOSSILS THE REMAINS OR IMPRESSIONS OF PLANTS OR
ANIMALS IN ROCK
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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.
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