4.1b Environmental O & H

Mechanisms of O and H fractionation

The water cycle

• Pools: groundwater, soil, ocean, biomass, atmosphere/air, clouds

• Fluxes: evaporation/condensation, transpiration, root uptake, precipitation, advection, sublimation, percolation, infiltration

Temperature Effect: Precipitation isotope delta values decrease as temperature increases

• Salinity is a good predictor of O values in the ocean because evaporation and circulation drive both

Continental effect / distance from source: precipitation isotope delta values decrease with distance from source (the ocean)

Latitudinal / Altitude effect: precipitation isotope delta values decrease with increasing latitude or altitude

Amount Effect: Precipitation isotope delta values decrease with increasing raingall because they rain out. Generally follos Rayleigh model

Isoscape Uses:

• Tracing movement (sea or land)

• Archives of past climate / paleo-climate

• Tracing origins of water

• Trace water-rock reactions (like hydrothermal vents)

References

Gat 1996

Summary of environmental fractionation, mostly of soil and atmosphere