SEDIMENTARY ROCKS MINERAL OR ROCK FRAGMENTS OR 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
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 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.

Beach
sand

Davidson 4.20


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

SEDIMENTARY
ROCK TYPES
Deposited by moderate
currents that removed

finer sediment: rivers,
coasts with moderate
waves, wind-produced
dunes.

Deposited by gentle
currents, so small
particles settle out of
the water: deep
ocean, coasts with
weak tides
Davidson 4.19


COMPACTION, LITHIFICATION, DIAGENESIS
UNCONSOLIDATED SEDIMENT TURNS INTO HARD
SEDIMENTARY ROCKS

Davidson 4.25

Similar 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
Davidson 4.24


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 AGOSOUTHERMOST ADVANCE OF
GLACIER THAT FLOWED
THROUGH LAKE MICHIGAN
BASIN AND INTO NE ILLINOIS
SINCE THEN, ICE MELTED
BACK

QuickTime™ and a
Photo decompressor
are needed to see this picture.

MAXIMUM
EXTENT OF
GLACIATION
LAST
2 MILLION
YEARS

Davidson 14.15


Earth’s orbit changes

MILANKOVITCH CYCLES
Earth’s tilt changes

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)


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 MORAINES
TILL 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

ILLINOIS 16,000 YRS AGO

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


CHEMICAL SEDIMENTS: CRYSTALLIZED FROM WATER WHEN THEIR
CONCENTRATION EXCEEDS THAT WHICH CAN BE DISSOLVED
(SOLUBLE) IN WATER
EVAPORITES - SALTS OF
SODIUM, CALCIUM, MAGNESIUM,
POTASSIUM DEPOSITED AS
DESERT LAKES, SEAS DRY UP.
EXAMPLESDEAD SEA
BONNEVILLE SALT FLATS
(GREAT SALT LAKE) REMAIN
FROM HUGE LAKE DURING ICE
AGES
MEDITERRANEAN (6 MYR AGO)

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


QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.

5-6 million years ago the
Mediterranean became
isolated from the Atlantic
Ocean, causing the sea
water to evaporate, and
leaving immense driedup basins, shown by a
large accumulation of

salt deposits sandwiched
between deep-water
marine sediments.

QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.


METAMORPHIC ROCKS- FROM ALTERATION OF PRE-EXISTING ROCKS
BY HEAT, PRESSURE, & CHEMICAL REACTIONS
CAN INVOLVE CHANGES IN
MINERALOGY, TEXTURE, &
CHEMICAL COMPOSITION

PRESSURE & TEMPERATURE
INCREASE WITH DEPTH

ALTHOUGH SHALLOW BURIAL
CAN PRODUCE LITHIFICATION &
DIAGENESIS OF SEDIMENT INTO
SEDIMENTARY 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
Davidson 4.26


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

Davidson 4.26


INTERNAL ENERGY
(HEAT) FROM EARTH
ACTS VIA PLATE
TECTONICS 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
Davidson 4.30

THE ROCK CYCLEINTERCONNECTIONS BETWEEN
ROCK-FORMING PROCESSES