CRUCIAL FACTORS:

SOURCE ROCK FROM WHICH SEDIMENT DERIVED

TRANSPORT MECHANISM (WIND, WATER, ICE)

SITE OF DEPOSITION (RIVER, LAKE, OCEAN, DESERT)

PLATE TECTONIC SETTING

SEDIMENTS 5% OF EARTH'S CRUST, BUT MOST COMMON SURFACE ROCKS, RECORD EARTH HISTORY, & VALUABLE FOR RESOURCES (oil, gas, coal, building material)

SEDIMENTARY ROCKS-MINERAL OR ROCK FRAGMENTS OR MATERIAL OF ORGANIC ORIGIN ARE ERODED OR DISSOLVED AND THEN DEPOSITED IN LAYERS AT EARTH'S SURFACE

SEDIMENTARY ROCK TYPES

CLASTIC SEDIMENTS: GRAINS PRODUCED BY MECHANICAL OR CHEMICAL WEATHERING AT EARTH'S SURFACE (EXAMPLE: SANDSTONE)

BIOCHEMICAL SEDIMENTS: MATERIAL OF ORGANIC (LIVING THINGS) ORIGIN SUCH AS SHELL OR CORAL FRAGMENTS (EXAMPLES: LIMESTONE, COAL)

CHEMICAL SEDIMENTS: INORGANIC CHEMICALS PRECIPITATED (CRYSTALIZED) FROM WATER (EXAMPLE: SALT DEPOSITS)

Size and shape of sedimentary grains reflects transportation history.

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Beach sand

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SEDIMENTARY ROCK TYPES

Large grains indicate transport and deposit by strong currents: mountain streams, beaches with large waves, or glacial melt streams

Deposited by gentle currents, so small particles settle out of the water: deep ocean, coasts with weak tides

Deposited by moderate currents that removed finer sediment: rivers, coasts with moderate waves, wind-produced dunes.

COMPACTION, LITHIFICATION, DIAGENESISUNCONSOLIDATED SEDIMENT TURNS INTO HARD

SEDIMENTARY ROCKS

Davidson 4.25Similar to snow turning to ice

Sedimentary Structures:

Cross-bedding: sediment carried by moving fluid (water, air)

Ripple Marks

Graded Bedding: grains become finer upward in layer

Mud Cracks: shallow water deposit

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MIDWEST HAS FEATURES FORMED BY SEDIMENT

TRANSPORTED BY GLACIERS

MANY FORMED 25,000 - 14,000 YRS AGO DURING LAST ICE AGE

VAST ICE SHEET OVER CANADA

GLACIERS FLOW AWAY FROM ICE SHEET'S CENTER

18,000 YRS AGO- SOUTHERMOST ADVANCE OF GLACIER THAT FLOWED THROUGH LAKE MICHIGAN BASIN AND INTO NE ILLINOIS

SINCE THEN, ICE MELTED BACK

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MAXIMUM EXTENT OF GLACIATION LAST 2 MILLION YEARS

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ECCENTRICITY, TILT, & PRECESSION CAUSE VARIATIONS IN SUNLIGHT (UP TO ABOUT 5% AT HIGHER LATITUDES), SO CLIMATE VARIES BETWEEN WARMER AND COLDER PERIODS.

COLDER WINTERS, MORE ICE ACCUMULATES, CAN START ICE AGE

OTHER FACTORS MAY ACT INCLUDING MOUNTAIN UPLIFT (HIMALAYA)

MILANKOVITCH CYCLESEarth’s orbit changes Earth’s tilt changes

GLACIERS- THICK ICE, LASTS ALL YEAR; RECRYSTALLIZED SNOW MOVES DOWNSLOPE BY GRAVITY OR RADIALLY OUTWARD BY ITS OWN WEIGHT

Robeson Glacier, Canada

GLACIERS ERODE & DEPOSIT SEDIMENT - TILL

ADVANCING GLACIERS SLOWLY PUSH EARTH & ROCK FORWARD DEPOSIT THESE MATERIALS WHEN GLACIERS MELT (RETREAT)

TILL - DEBRIS DEPOSITS, POORLY SORTED FORM CHARACTERISTIC LANDFORMS

END MORAINESTILL DEPOSITS AT GLACIER

MARGIN

Sheridan Road, Winnetka

Glencoe Beach

Glacial Park, McHenry

Palos Park

Kettle Morraine State Forest, WI

DRUMLINS

ROUNDED & ELONGATED HILL OF GLACIAL TILL

BUILT UNDER ICE MARGINS SHAPED BY GLACIERS FLOW

BLUNT NOSE IN DIRECTION FROM WHICH ICE CAME & GENTLE SLOPE TAPERED IN OTHER DIRECTION

ESKERS

LONG SAND & GRAVEL RIDGES LEFT BY SEDIMENT IN MELTWATER TUNNELS UNDER GLACIER

VOLO BOG (McHENRY, IL)- A KETTLE LAKE

FORMED 15,000 YEARS AGO WITH GLACIER'S RETREAT

LEFTOVER LARGE BLOCKS OF ICE ON GROUND

MELTS AS CLIMATE WARMS

FORMS KETTLE-HOLE DEPRESSION

EVENTUALLY FILLS

RETREATING GLACIERS; MUCH STILL UNDER ICE

RECENTLY DEGLACIATED AREAS COVERED WITH BARE SHEETS OF TILL & SLOWLY REVEGETATED

LARGE LAKES WHERE MORRAINES DAM WATER COMING OFF MELTING GLACIERS

LAKES, MARSHES, AND BOGS COMMON

COOLER CLIMATE- DIFFERENT PLANTS AND ANIMALS THAN TODAY

ILLINOIS 16,000 YRS AGO

EVAPORITES - SALTS OF SODIUM, CALCIUM, MAGNESIUM, POTASSIUM DEPOSITED AS DESERT LAKES, SEAS DRY UP.

EXAMPLES-

DEAD SEA

BONNEVILLE SALT FLATS (GREAT SALT LAKE) REMAIN FROM HUGE LAKE DURING ICE AGES

MEDITERRANEAN (6 MYR AGO)

CHEMICAL SEDIMENTS: CRYSTALLIZED FROM WATER WHEN THEIR CONCENTRATION EXCEEDS THAT WHICH CAN BE DISSOLVED (SOLUBLE) IN WATER

GREAT SALT LAKE - UTAH LATEST OF LAKES THAT EXISTED OFF AND ON FOR PAST 15 MYRS.

NO OUTLET BECAUSE AT BOTTOM OF A BASIN. FRESH WATER ENTERING FROM RIVERS CAN ONLY EXIT BY EVAPORATION OR SEEPAGE INTO DEEP GROUNDWATER LAYERS.

CURRENT CLIMATE OF HIGH EVAPORATION AND LOW INPUT OF FRESH WATER GIVES SALINE LAKE.

SALT WATERS’ MAJOR ELEMENTS: SODIUM, MAGNESIUM, POTASSIUM, CHLORIDE, AND SULFATE.

MAJOR MINERAL INDUSTRY

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5-6 million years ago the Mediterranean became isolated from the Atlantic Ocean, causing the sea water to evaporate, and leaving immense dried-up basins, shown by a large accumulation of salt deposits sandwiched between deep-water marine sediments.

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CAN INVOLVE CHANGES IN MINERALOGY, TEXTURE, & CHEMICAL COMPOSITION

ALTHOUGH SHALLOW BURIAL CAN PRODUCE LITHIFICATION & DIAGENESIS OF SEDIMENT INTOSEDIMENTARY ROCK, ONLY PLATE TECTONIC PROCESSES CAN CAUSE PRESSURES AND TEMPERATURES HIGH ENOUGH TO PRODUCE METAMORPHIC ROCKS

METAMORPHIC ROCKS INDICATE TEMPERATURE & PRESSURE CONDITIONS UNDER WHICH THEY FORMED

METAMORPHIC ROCKS- FROM ALTERATION OF PRE-EXISTING ROCKS BY HEAT, PRESSURE, & CHEMICAL REACTIONS

Davidson 4.26

PRESSURE & TEMPERATURE INCREASE WITH DEPTH

METAMORPHIC ROCKS: MARBLE

HEAT AND PRESSURE METAMORPHOSE LIMESTONE INTO MARBLE

Metamorphic rocks formed by increasing pressure/temperature on a mudstone to

slate,

then schist,

then gneiss,

then remelted & recrystallized

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INTERNAL ENERGY (HEAT) FROM EARTH ACTS VIA PLATETECTONICS TO CAUSE VOLCANISM & MOUNTAIN BUILDING

EXTERNAL ENERGY FROM SUN CAUSES WEATHER, THUS WEATHERING, EROSION, TRANSPORTATION, & DEPOSITION OF SEDIMENTS

ROCKS BURIED, METAMORPHOSED, MELTED & UPLIFTED BY TECTONIC PROCESSES

THE ROCK CYCLE- INTERCONNECTIONS BETWEEN ROCK-FORMING PROCESSES

Davidson 4.30