Movement of iron and aluminum in a series of palesols on a parabolic dune at Cape Kiwanda, Oregon
Karen R. Carroll, Mary Dietrich, and Scott F. BurnsPortland State UniversityDepartment of Geology
LocationCape Kiwanda
Paleosols in sand dune
3rd Paleosol up (from bottom)
Objectives
• Are Fe and Al increasing, decreasing, or neither in the soils overall as soil development age increases?
• Is translocation of Fe and Al occurring from the A B horizons or from upper B lower B horizons?
• Is spodosol development occurring?
Paleosol 1 (P1) - Typic Eutropsamment
Ab
Bwb
Ab
Btjb
Bwb
Paleosol 2 (P2)
Typic Humitropept
Paleosol 3 (P3)
Typic Humitropept
Ab
Btjb
Bwb
Paleosol 4 (P4)
Typic Humitropept
Ab
Bwb
Ab (P3)
Methods
• Citrate-Dithionite extraction for Fe and Al (modified Mehra and Jackson, 1960)
- new rotational method
• Acid-Oxalate extraction for Fe and Al (modified McKeague and Day, 1966)
- new rotational method
• Atomic Absorption Spectrometer
Iron (ppm)Paleosol Horizon Fe (ppm) Soil Dev
Dithionite Std Dev Oxalate
Std Dev
Age (yrs)
P4 Ab 67.8 2.4 21.9 1.7 170
Bwb 43.5 0.2 14.3 1.9 Ab 64.0 2.7 22.8 2.9 850
P3 Btjb 40.8 1.6 10.6 0.1 Bwb 31.0 0.4 9.4 0.6 Ab 90.7 1.4 40.8 2.2 1420
P2 Btjb 45.2 1.4 20.6 0.2 Bwb 41.3 0.9 20.1 4.4
P1 Ab 73.2 1.9 31.4 0.5 1010 Bwb 60.1 1.4 28.0 1.7
Aluminum (ppm)
Paleosol Horizon Al (ppm) Soil Dev
Dithinonite Std Dev Oxalate
Std Dev
Age (Yrs)
P4 Ab 30.4 1.8 29.4 3.1 170
Bwb 15.4 0.8 14.5 1.6 Ab 25.1 1.4 21.7 4.3 850
P3 Btjb 17.0 0.6 14.3 0.2 Bwb 18.3 0.5 18.7 1.6 Ab 36.2 1.0 35.8 3.7 1420
P2 Btjb 22.8 1.4 23.7 3.6 Bwb 24.3 1.0 27.8 4.5
P1 Ab 11.5 0.8 9.3 0.8 1010 Bwb 11.7 2.8 7.3 10.3
Conclusions• As soil development age increases past 1000 years, Fe
and Al increase
• Leaching of Al between buried B horizons occurs in two of the four soils and indicates that leaching begins to occur by 820 years of soil development
• Leaching of Fe does not begin until sometime after 1420 years of soil development
• There are no E horizons present (yet)
• Future work could include subdividing A horizons to look for Fe/Al anomolies that could lead to an E horizon
Acknowledgements
We would like to thank Ben Perkins, Sherry Cady, and Marina Drazba of Portland State University for equipment use and assistance, supplies, expertise and creative ideas, and Amanda Carroll for lab assistance
