Transcript GLACIERS - Heartland

GLACIERS
Chapter 6
Test 3 material
ASSIGNMENT
• 1 –2 PAGE
REPORT DUE IN
ONE WEEK ON
“HOW GLACIERS
HAVE IMPACTED
THE
LANDSCAPE IN
ILLINOIS”
ICEBERG
GLACIER
• LARGE MASS OF ICE, RESTING
ON LAND OR FLOATING AS AN
ICE SHELF IN THE SEA
ADJACENT TO LAND
• 85% OF ALL GLACIAL ICE IS IN
ANTARCTICA
Glaciers
EIZEIT
• TERMED COINED BY SWISS
SCIENTIST, LOUIS AGASSIZ TO
DESCRIBE THE COLD PERIODS
ON EARTH
• TRANSLATED IT MEANS “ICE
AGE”
SNOWLINE
• THE LOWEST ELEVATION
WHERE SNOW CAN SURVIVE
YEAR-ROUND
• HIGHER ELEVATIONS IN
EQUATORIAL AREAS
• LOWER ELEVATIONS IN POLAR
AREAS
TYPES OF GLACIERS
ALPINE
• MOUNTAINOUS AREAS
• VALLEY GLACIER IS CONFINED
TO A STREAM FORMED VALLEY
IN A MOUNTAIN AREA
ALPINE GLACIER
TYPES OF GLACIERS
CONTINENTAL
• ICE SHEET
• ICE CAP
• ICE FIELD
HOW DO GLACIERS
FORM?
• SNOW THAT SURVIVES THE
SUMMER AND INTO THE
FOLLOWING WINTER BEGINS A
SLOW TRANSFORMATION
PROCESS. TAKES MAYBE 200
FEET OF ICE TO APPLY
PRESSURE FOR THIS
CONVERSION TO TAKE PLACE
ANATOMY OF A
GLACIER
• FRACTURE ZONE - THIS IS
WHERE WE FIND CREVASSES
THAT EXTEND DOWNWARD 200
FEET
• PLASTIC ZONE - OOZE & FLOW
• FRICTION ZONE - SLOWED BY
BEDROCK
GLACIAL BALANCE
• ACCUMULATION
• ABLATION
• GLACIER RETREATS IF
ABLATION EXCEEDS
ACCUMULATION
• GLACIER ADVANCES IF
ACCUMULATION EXCEEDS
ABLATION
GLACIAL EROSION
• ICE HAS NO EQUAL IN
TRANSPORTING SEDIMENT
FROM ONE LOCATION TO
ANOTHER
• CAN CARRY BOULDER-SIZED
MATERIAL HUNDREDS OF MILES
AWAY FROM ORIGIN
TYPES OF GLACIAL
EROSION
• ABRASION - ICE CARRIES ROCK
FRAGMENTS AND FILES AND
GRINDS SOLID ROCK
PRODUCING STRIATIONS
• PLUCKING - ICE LOOSENS
BLOCKS OF ROCK UPWARD
CONSOLIDATING THEM INTO
THE MASS OF ICE
STOSS & LEE
TOPOGRAPHY
• STOSS SIDE HAS ABRASION
• LEE SIDE HAS PLUCKING
• PRODUCES ROCHE
MOUTONNEE
GLACIAL EROSION
• STREAMS PRODUCE V-SHAPED
VALLEYS
• GLACIERS FLOW INTO THESE
AND CHANGE THEM TO USHAPED TROUGHS
ALPINE EROSIONAL
FEATURES
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ARETES
COL - PASS
HORN
TARN
PATERNOSTER
CIRQUE
ARETES
• HANGING VALLEY
• FJORD OR FIORD
DEPOSITIONAL
FEATURES
• DRIFT - TERMED USED FOR ALL
GLACIAL DEPOSITS
• TILL - UNSORTED MATERIAL
LEFT BY GLACIERS
• OUTWASH - SORTED MATERIAL
LEFT BY MELTING GLACIAL
STREAMS
• GLACIAL ERRATICS
GLACIAL TILL
MORAINES
RIDGES OF TILL
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LATERAL - SIDES OF GLACIER
MEDIAL - TWO LATERALS JOIN
END - AT END OF GLACIER
TERMINAL - ULTIMATE
ADVANCE OF GLACIER
• RECESSIONAL - AS GLACIER
EBBS AND RETREATS
• GROUND - DEPOSITS IN AN
AREA ONCE OCCUPIED BY
GLACIER
DEPOSITIONAL
FEATURES
• ESKER - SINUOUS RIDGES OF WELLSORTED SAND AND GRAVEL THAT
ARE FORMED IN STREAM TUNNELS
UNDER A STAGNANT GLACIER
• OUTWASH PLAIN - AREA IN FRONT
OF END MORAINE THAT IS FLAT DUE
TO GLACIAL MELTWATER DEPOSITS
• KAME - SMALL HILL OF POORLY
SORTED SAND AND GRAVEL
• KETTLE - MELTED ISOLATED BLOCK
OF ICE LEFT BY GLACIER
• DRUMLIN - ELONGATED
STREAMLINED HILLS COMPOSED OF
EVERY TYPE OF DRIFT - BUNKER
HILL
DRUMLIN
•
• http://www.pma.edmonton.ab.ca/
vpub/geology/english/mineral.ht
m
PLEISTOCENE ICE AGE
• CONSISTS OF GLACIAL
PERIODS (WHEN CONTINENTAL
ICE SHEETS EXTENDED
SOUTHWARD) AND
INTERGLACIAL PERIODS (WARM
PERIODS WHEN ICE RETREATED
TO POLAR REGIONS)
GLACIAL
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NEBRASKAN
KANSAN
ILLINOIAN
WISCONSINAN
INTER GLACIAL
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AFTONIAN
YARMOUTHIAN
SANGAMONIAN
POST GLACIAL (RECENT)
WHAT CAUSED
CLIMATE TO CHANGE?
• MILUTAN MILANKOVITCH, A
YUGOSLAVIAN SCIENTIST
CLAIMED THAT THE EARTH’S
ORBIT MIGHT NOT HAVE BEEN
CONSTANT AROUND THE SUN
OR THE EARTH’S AXIS
WOBBLES OR CHANGES ITS
TILT
PERIGLACIAL
• PERIMETER OF GLACIATION
• PERMAFROST - PERMANENTLY
FROZEN GROUND. WATER IN
GROUND IS FROZEN BELOW THE
SURFACE AS CLOSE AS 6 INCHES TO
161/2 FEET BELOW SURFACE
• ACTIVE LAYER IS ABOVE THE
PERMAFROST
PERIGLACIAL
FEATURES
• FROST WEDGING - SHATTERING OF
ROCK WITHIN THE ACTIVE LAYER
• FROST HEAVING - UPWARD
MOVEMENT OF ROCK LOOSENED BY
WEDGING
• FROST THRUSTING - ROCK
FRAGMENTS MOVE HORIZONTALLY
Frost wedging
PERIGLACIAL
FEATURES
• PINGOS - MOUND LIKE HILLS
WITH AN ICE CORE
• FELSENMEER - SLOPES
COVERED BY BLOCKY PIECES
OF ROCK COVERING A LARGE
AREA
PINGO