Subglacial Water in Antarctica At the Intersection of Many Disciplines

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Subglacial Water in Antarctica At the
Intersection of Many Disciplines

• Dr. Robin E. Bell
• Lamont-Doherty Earth Observatory
• Columbia University
• AISS Workshop NSF June 2007

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• Continental Tectonics GeoDynamics

Sub Glacial Water
Life in Extreme Environments
Ice Sheet Dynamics
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Outline

• Water - Intro
• Ice Sheet and Ecosystems
• Water and Tectonics
• Tectonics and Ice Sheet Dynamics

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DOME A
DOME A
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First Antarctic Subglacial Lake 1970s

• Gordon Robins Interpretation of SPRI radar data

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Far More Water than Anticipated

• Boreholes Vostok (lake), EPICA-Dronning Maud
  (water), Dome F (melting), Dome C (melting), WAIS
  - lots of water
• Radar Bright Reflectors
• Surface Elevation Capture Elevation Change

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Recovery Lake A is 3910 km2 Recovery Lake B is
4380 km2 Recovery Lake C is 1490 km2 Recovery
'Lake D' is 3540 km2
A
B
C
D
S
90
V
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Radar Line Over Lake Vostok
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Ice Core Analysis and Aerogeophysics Reveals
Dynamics ---- Not Very Fast --- cm/yr
melt/freeze and Residence times of 50,000
yearWater Is not 35 My but nat what you would
call dynamic system
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SUBGLACIAL RIVERSImproved Satellite Imaging of
Ice Sheet Surface Detects ChangesWingham et al
(2006) The Thames of East AntarcticaGray et al
in West AntarcticaMuseums no More
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Fricker et al Capture A Collapsing Lake in West
Antarctica
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Recovery Ice Stream Triggers Onset Streaming
(Bell et al)
1/3 - the relationship of the flow features
between Recovery Lakes and the Recovery Glacier
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• Continental Tectonics GeoDynamics

Sub Glacial Water
Life in Extreme Environments
Ice Sheet Dynamics
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Lakes
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Material From Accreted Ice
Pollen (Burckle)
Bacteria (Karl et al)
Lake Ecosystems Isolated Free Exchange with the
Atmosphere for Possible 35 MY
Fungus (Burckle)
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Melting and Freezing of Ice Sheet Above Lakes
Melting in Upstream Catchment Region Controls
Fluxes into Subglacial Lakes
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• Melting and Freezing Not Uniformly Distributed

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Subglacial Ecosystems

• Fluxes strongly controlled by
• Ice Sheet Dynamics
• Melting and Freezing Distribution Control Lake
  Chemistry
• Cycle of Fill/Drain Influence Longevity of
  Ecosystem
• Underlying Tectonics
• Heat Flow
• Crustal Fluid Flow

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Antarctic Images
RIS
Ross Sea
NASA GSFC Scientific Visualization Studio
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• Continental Tectonics GeoDynamics

Sub Glacial Water
Life in Extreme Environments
Ice Sheet Dynamics
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• Subglacial Topography
• Lake Elevation

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Long Lines Vostok SurveyMagnetic Anomaly
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Long Lines Over Lake Vostok Gravity Anomaly
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Resulting ModelThrust sheet emplaced onto
former margin
Lake Vostok
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Tectonic Control of Large Subglacial Lakes
Vostok

• Recovery

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• Tectonic Framework of East Antarctica
  Reconstructed with India and Australia
• From Fitzsimons (2003) with location of large
  subglacial lakes Recovery R, Sovetskaya (S), 90E
  (E), Vostok (V) and Astrolabe (A) as well as Dome
  C lake district and Lake Concordia (C). GSM
  indicates the Gamburtsev Subglacial Mountains,
  DML Dronning Maud Land.

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• Continental Tectonics GeoDynamics

A
B
Subglacial Water
Life in Extreme Environments
Ice Sheet Dynamics
C
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Distribution of Basal Meltie How Much Water
Available.

• Strongly Controlled by
• Climate and Tectonicsgt
• Ice Sheet Geometry
• Surface Temperature
• Basal Heat Flow

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Control of Ice Streaming Onset by Underlying
Tectonic Framework

• Bell et al

• Anandakrishnan et al

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Recovery Lakes - Recovery Glacier - Velocities
3/3 - the relationship of the flow features
between Recovery Lakes and the Recovery Glacier
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Lake Vostok Hydraulic Potential
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Dry Valleys Labyrinth - Timing Volume -- Linkages
to Ocean Circulation
Water mobility from Vostok and other subglacial
lakes has recently been confirmed. (Lewis,
A.R.,et al, Geology.) Oblique view of major
subglacial outburst flood erosion feature in East
Antarctica from Twin Otter by R. Swift
(WFF/GSFC/NASA).
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Summary

• Subglacial Water Critical Interface Between
• Ecosystem Dynamics
• Geosynamics
• Ice Sheet Dynamics

GeoDynamics
Sub Glacial Water

• Ecosystems
• Dynamics

• Ice Sheet Dynamics