Mössbauer Study of the Attenuation of Iron in an Irrigated Greensand Lysimeter

C. A. M. Ross and G. Longworth
Institute of Geological Sciences, Atomic Energy Research Establishment Harwell, Oxfordshire, OX11 0ra, United Kingdom
Nuclear Physics Division, Atomic Energy Research Establishment Harwell, Oxfordshire, OXI1 0RA, United Kingdom

Abstract: Fe57 Mössbauer spectroscopy has been used to determine the nature of iron-containing minerals in Lower Greensand samples from an experimental lysimeter at Uffington, Oxfordshire, both before and after a three-year irrigation with a synthetic heavy metal leachate. Analysis of the spectra measured at 300°C 77°C and 4.2°K and at 4.2°K in an applied field of 45 kOe shows that iron is present in the uncontaminated sandstone in fine-grained goethite (α-FeOOH) and glauconite. In the irrigated samples iron is precipitated as a fine-grained ferric hydroxide gel having values for the hyperfine field at 4.2°K of 435 and 470 kOe. The stability of the gel over the three-year period of irrigation may be explained by surface energy considerations.

Key Words: Glauconite • Goethite • Greensand • Iron • Lysimeter • Mössbauer spectroscopy

Clays and Clay Minerals; February 1980 v. 28; no. 1; p. 43-49; DOI: 10.1346/CCMN.1980.0280106
© 1980, The Clay Minerals Society
Clay Minerals Society (www.clays.org)