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