CONTINENTAL ICE SHEET - GREENLAND
ALPINE ICE- VALLEY GLACIER(S)
GLACIER BAY, ALASKA
ALL GLACIERS HAVE TWO ZONES
ACCUMULATION = + MASSABLATION = - MASS
“Firn Line” = Equilibrium Line
Italian alps
Dinwoody Glacier. Wind River Range, Wyoming.
GAME OF MASS BALANCE
SNOW IN vs WATER/ICE OUT
IDEALIZED MOTION- CROSS SECTION
= strain rate
A = constant related to ice temperature
= basal shear stress (?)
n = exponent with an average value of 3
GLEN’S FLOW LAW
gh sin
TEMPERATURE MATTERS
Does cold or warm ice strain more
rapidly?
STRESS-STRAIN RESPONSE
(WATER)
(DEBRIS FLOW)
MASS FLUX - BIRD’S EYE VIEW
VELOCITY DISTRIBUTION - BIRD’S EYE
VELOCITY IN SECTION VIEW
WHAT’S GOING ON AT THE BED????
WHAT IS THE TEMPERATUR
E AT THE BASE OF THE
ICE?
-GEOTHERMA
L-FRICTION-AMBIENT
AIR
WARM BASED ICE
sliding along bed
FOX GLACIER, New Zealand
COLD-BASED ICE
frozen to bed
DRY VALLEY AREA-- ANTARTICA
COMPARE, WARM VS COLD
UIMPLICATIONS FOR EROSION
INTENSITY
CLASSIC U-SHAPED VALLEY
EROSION REQUIRES
WARM BASED ICE,
WHY?
PLUCKING….
PLUCKING IN ACTION
ABRASION -STRIATIONS AND POLISH
ABRASION TAKES TOOLS
“THE DIRT
MACHINE”
GLACIERS AS A CONVEYOR BELT
FOR ROCK DEBRIS
WHERE DOES ERODED MATERIAL GO?
MORAINE FORMATIONINDICATES A STILL STAND
MORAINES
LATERAL
LATERA
L
TERMINAL
Frans Joseph Glacier - Tom Lowell
MASSIVE COASTAL
MORAINES
MORAINES ARE SCARCE IN INTERIOR NEW ENGLAND --
IMPLIES RAPID, DYNAMIC ICE MARGIN RETREAT (KOTEFF
AND PESSL)
OUTWASH PLAINS FROM WATER CARRIED DEBRIS
PRESENT DAY OUTWASH -- MT COOK
SEDIMENT DELIVERY TO ICE MARGINAL LAKES
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LAKE SEDIMENTS
TASMAN GLACIER
TILL - NOT WELL
WASHED BY WATER
BASAL VS MELTOUT
SIERRA NEVADA, ALPINE
CENTRAL MASS, CONTINENTAL
ESKER
DRUMLIN - STREAMLINED FEATURE
KETTLED TERRAIN
KETTLE FORMING TODAY
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