continental ice sheet - greenland alpine ice- valley glacier(s)

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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