Permafrost-Influenced Geomorphic Processes
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Permafrost-Influenced Geomorphic Processes
Torre Jorgenson
environmental research & servicesenvironmental research & services
Overview of Geomorphic Processes• Coasts
– Storm surges, sedimentation, salinization, permafrost degradation• Floodplains
– Changing flooding, sedimentation, – Channel migration
• Coastal Plain-Lowlands– Thermokarst lakes, waterbody creation– Lake expansion and shrinkage – Paludification, organic matter accumulation– Ice-wedge Degradation
• Uplands– Loss of permafrost aquatard, drainage– Thaw slumps– Thermokarst Lakes in Extremely ice-rich loess (yedoma)
• Mountains– Slope Failure
North Slope Ecological ProfileC
oast
al W
ater
Coa
stlin
e
Jago Coastal Plain
Flo o
dpla
in
Up
lan
ds
Glaciated Uplands
I cy Coast
Coastal Plain
OkpilakMountains
Sadlerochit Uplands
Lakes
Lowland sDwarf Shrub
edge-
Lacustrine Wet S eadowedge M
Upland Tussock Tundra
Coastal WetSedge Tundra
Coastal Grass and Dwarf Shrub Tundra
Mesic shurbbytussock tundra
Upland Low birch-Willow shrub
Upland Tall Alder Shrub
River
Riverine Barrens
Riverine low willow shrub
Riverine Dryas
Riverine Wet Sedge Meadow
Alpine acid barrens
Alpine Dryas Dwarf Shrub
Intrusive,felsic
Quaternary,glacial
Sedimentary,NoncarbonateQuaternary,
alluvial-marineQuaternary,marine
Hula
hula
Mounta
ins
Beaufort Coastal Plain
Brooks Foothills
Beaufort Coast
0
500
1000
1500
2000
2500
3000
Elev
atio
n (m
)
Brooks Range
IntrusiveFelsic
Quaternary,Alluvial
Coastal Ecosystems
• Sedimentation (up to 10 cm in big year)
• Storm Surges (1970 to 2 m)
• Salinization (up to 15 km inland)
• Sea Level Rise (3 mm/yr)
Barrier Island and Lagoon Ecosystems
Tundra Cliff and Sandy Shore Ecosystems
Delta Ecosystems
Summer
DON
DOC
NO3
ThermokarstSalinity
Temperature
Wind
Organic Mat
Ground ice
PO4
Active Dunes
Inactive Dunes Tidal
Flats
Precipitation
Sea Level
Wave Energy
Sea
Sediment
Discharge
Winter
Produced for ARCN-NPS by M. T. Jorgenson and D. M. Sanzone
OCEANOGRAPHIC ¯
Sea Level Storm surges Sea Ice Fetch Length Wave Energy
GEOMORPHIC Shoreline Erosion Barrier Island Migration Marine Sedi. Transport Land Sediment Deposit. Dune Formation/Scouring Thermokarst
DDDD
CHANGE
Coastal Geomorphic Processes
October 2002 Storm at Barrow
2000 Beaufort Lagoon
-1.0
-0.5
0.0
0.5
1.0
1.5
7/13/2000 7/23/2000 8/2/2000 8/12/2000 8/22/2000 9/1/2000 9/11/2000 9/21/2000
DATE
WA
TE
R L
EV
EL
(m)
Mininum
MaximumMean tidal range = 0.31 m
1.0 m on 11-12 August
Storm Surges
Coastal Erosion
Deltaic Environments
Salinization: Salt-killed tundra
FLUVIAL PROCESSES
Changing flooding, sedimentation, Channel migration
Changes over Time:
Increasing height,
Decreasing flooding frequency,
Decreasing sedimentation,
Increasing organics,
Decreasing thaw depths,
Decreasing water depths
Decreasing pH
Increasing ground ice,
Increasing susceptibility to thermokarst,
GEOMORPHIC PROCESSES ON RIVER FLOODPLAINS
Upland Sandy Low
Scrub
Upland Barrens
Riverine Barrens
Riverine Low and
Tall Scrub
Riverine Wet
Meadow
Lowland Wet
Meadow
Lowland Deep Lake
Riverine Wet
Meadows
Riverine Lake -
Connected
Riverine Marsh
1000-2000 years for development
Low Water
1-2 yr3-4 yr
5-25 yr
25-200 yr
Massive or Crossbedded Sand
Rippled sands/fines, with detrital organicsLayered fines
Masssive organics
Layered fines w/ clay
Layered Organics
Eco
typ
es
Decreasing Flooding and Sedimentation
Riv
er
Riverbed/ Riverbars
Active-floodplain
Cover Deposit
Inactive-floodplain
Cover Deposit
Abandoned- floodplain
Nuiqsut
Eas
t Cha
nnel
Col
ville
Riv
er
Nech
elik
Channel
Eroded Riverbed/Sandbar
Riverbed/Sandbar Deposition
Unchanged Riverbed/Sandbar
Thaw Basin Drainage/Deposition
Other Eroded Terrain
Unchanged Terrain
Lake-level Change
Unchanged Water
In-field Facilities
Pipelines
N 0
SCALE IN MILES
Proposed Project
Areas of Erosion and Deposition
1 2
Area (%)1.3
2.6
7.6
1.8
1.0
58.8
0.9
26.1
Landscape Change from 1955 to 1992,Central Colville River Delta
8.2% of area changed over 37 yr2.3% of land erodedAt current rate it would take about 1700 years to rework entire delta
Erosion and Deposition
Lowland and Lacustrine Ecosystems
Lowland Hydrology:8-11 ka surfacePoorly integrated surfaceSnow-melt rechargeSummer Draw-down
Coastal Plain Geomorphic Model
Eolian SandLoess
Thaw Lake
Coastal Plain with Moist/ Dry Tundra
Ice-rich Thaw Basin with Wet Tundra Ice-poor Thaw Basin
with Wet Tundra
1992Jun AugJul
1991Jun AugJul
-500
-400
-300
-200
-100
0
100
200
1990
Jun AugJul
Class A Pan Evaporation
Net Water Balance
Precipitation
NE
T W
AT
ER
BA
LA
NC
E (
mm
)
Shoreline Erosion and Lake Basin Development
0.7% of land was eroded over 45-56 year period, 0.01%/yrAt this rate it would take 8400 years to rework the surface.
In-filling of Lake Margins
1945
Wetting location
Drying location
Time Series: Beaufort Coastal Plain
1982
Pond shifts
Pond develops
2001
Pond drains
Pond develops
Ponds drains
1982
2001
Micro-topographic Effects of Ice-wedge Degradation
Alluvial-marine Deposit(gently rolling)
Ice-poor Thaw Basin
Ice-rich Thaw Basin Margin
Before Disturbance
Thermokarst After Disturbance
Shallow Water
Deep and Shallow Water
Wet Tundra, Deep and Shallow Water
Before DisturbanceActive Layer (m)Segregated Ice (% vol)Wedge ice(% vol)
After DisturbanceActive Layer (%)Mound Settlement (m)Trough Settement (m)Drainage
0.3 0.4 0.3 0.4 0.471 64 64 64 6020 15 20 15 0
0.8 0.8 0.8 0.8 0.80.6±0.3 0.4±0.3 0.3±0.1 0.4±0.3 0.4±0.3
1-2 1-2 1-3 1-2 0partial none none/partial none none
Water
Active Layer
Ice Wedges
Ice-rich Thaw Basin Center
Ice-rich Thaw Basin Margin
Deep and Shallow Water
Deep Water
Alluvial-marine Deposit(gently rolling)
Ice-poor Thaw Basin
Ice-rich Thaw Basin Margin
Before Disturbance
Thermokarst After Disturbance
Shallow Water
Deep and Shallow Water
Wet Tundra, Deep and Shallow Water
Before DisturbanceActive Layer (m)Segregated Ice (% vol)Wedge ice(% vol)
After DisturbanceActive Layer (%)Mound Settlement (m)Trough Settement (m)Drainage
0.3 0.4 0.3 0.4 0.471 64 64 64 6020 15 20 15 0
0.8 0.8 0.8 0.8 0.80.6±0.3 0.4±0.3 0.3±0.1 0.4±0.3 0.4±0.3
1-2 1-2 1-3 1-2 0partial none none/partial none none
Water
Active Layer
Ice Wedges
Water
Active Layer
Ice Wedges
Ice-rich Thaw Basin Center
Ice-rich Thaw Basin Margin
Deep and Shallow Water
Deep Water
Stable Permafrost
Degrading Permafrost
Alluvial-marine Deposit(gently rolling)
Ice-poor Thaw Basin
Ice-rich Thaw Basin Margin
Before Disturbance
Thermokarst After Disturbance
Shallow Water
Deep and Shallow Water
Wet Tundra, Deep and Shallow Water
Before DisturbanceActive Layer (m)Segregated Ice (% vol)Wedge ice(% vol)
After DisturbanceActive Layer (%)Mound Settlement (m)Trough Settement (m)Drainage
0.3 0.4 0.3 0.4 0.471 64 64 64 6020 15 20 15 0
0.8 0.8 0.8 0.8 0.80.6±0.3 0.4±0.3 0.3±0.1 0.4±0.3 0.4±0.3
1-2 1-2 1-3 1-2 0partial none none/partial none none
Water
Active Layer
Ice Wedges
Ice-rich Thaw Basin Center
Ice-rich Thaw Basin Margin
Deep and Shallow Water
Deep Water
Alluvial-marine Deposit(gently rolling)
Ice-poor Thaw Basin
Ice-rich Thaw Basin Margin
Before Disturbance
Thermokarst After Disturbance
Shallow Water
Deep and Shallow Water
Wet Tundra, Deep and Shallow Water
Before DisturbanceActive Layer (m)Segregated Ice (% vol)Wedge ice(% vol)
After DisturbanceActive Layer (%)Mound Settlement (m)Trough Settement (m)Drainage
0.3 0.4 0.3 0.4 0.471 64 64 64 6020 15 20 15 0
0.8 0.8 0.8 0.8 0.80.6±0.3 0.4±0.3 0.3±0.1 0.4±0.3 0.4±0.3
1-2 1-2 1-3 1-2 0partial none none/partial none none
Water
Active Layer
Ice Wedges
Water
Active Layer
Ice Wedges
Ice-rich Thaw Basin Center
Ice-rich Thaw Basin Margin
Deep and Shallow Water
Deep Water
Stable Permafrost
Degrading Permafrost
Water-tracks
Hillslope Geomorphic Processes
Increased drainage, south-facing slopesThaw slumpsThermokarst Lakes in extremely ice-rich loess (yedoma)
Foothills Model
Precipitation- Leaching Gradient
Snow PhenologySpring
Fall
Thermokarst Gullies and Water Tracks, Healy
Thaw Slumps
Photo by Andrew Balser
Deep Thermokarst Lakes
Seward Peninsula
CONCLUSIONS
• Regional Factors– Cold climate leading to permafrost development
• Coastal Processes (16% of Coastal Plain including Lagoons, 5% land)– Sediment deposition, salinization, thermokarst– Spread of halophytic vegetation, salt-killed tundra
• Fluvial Processes (9% of area)– Flooding leading to sediment deposition– Channel migration, erosion, and thaw lakes– Feedback from ice aggradation of flooding regime– Willow thickets, legumes, productive wet sedge
Lacustrine Processes (14% areas in lakes, 39% in basins) Differential sediment deposition Shoreline Erosion (0.1%/yr) Lake Drainage (3% of landscape over 100’s yrs) Carbonate inputs, strong pH gradientsThermokarst
Ice Wedge Degradation (>3%, up to 20%)Tussock loss, wet sedge increase, redistribution of water
Hillside ProcessesDeeper Drainage,Gully formation, Thaw slumpsDeep Thermokarst Lakes
CONCLUSIONS
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