Hydrochemical Study of the Linnebreen Catchment

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Hydrochemical Study of the Linnebreen Catchment

• Fran Moore

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Chemical Weathering in the Linne Catchment

• What kind of chemical weathering is occurring in
  Linnedalen?
• Where is it happening?
• Is there any temporal variation?

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• Weathering reactions
• CaCO3 H2O ? Ca2 HCO3- OH- Carbonate
  hydrolysis
• CaCO3 H2O CO2 ? Ca2 2HCO3- Carbonate acid
  hydrolysis
• Pyrite Carbonate ? Ca2 HCO3- SO42- Iron
  hydroxide Pyrite oxidation with carbonate
  dissolution
• Silicates CO2 ? (Ca2, Na, K) HCO3- Clays
  Silicate Weathering

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Sampling
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Geographical Variability

• Do streams draining different areas have
  different chemical signatures?
• Can any inferences about residence time be made
  from solute content?
• Can solute changes along Linne elva be explained
  solely by inputs from source waters?

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Temporal Variability

• Is there any variation over 3 weeks of sampling?
• What difference (if any) between upper and lower
  sites?
• Calculation of total solute flux and possibly CO2
  drawdown compare glacial/pro-glacial zone with
  whole valley

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ISCO sampling
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ISCO sampling

• 24 samples from last 48-hour run at upper ISCO
• Test for any diurnal variation
• Possibly useful for examining weathering rates in
  the stream

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Results So Far

• Not Much!
• Discharge estimates from tributaries
• Some pH

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Work for Next Year

• Alkalinity titrations for bicarbonate SOON!
• Chlorine, sulfate, nitrate on ion chromatograph
• Ca, Mg, Na, K, Sr, Ba, Mn, Si on ICP-OES
• Kongress sulfur isotopes?

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Potential Problems ?

• Not enough sample for all tests
• Getting titrations done soon
• System being more complicated than planned
• Not enough distinctive variations in chemistry
• Limited significance of sampling method