150 likes | 255 Views
Rates of Magnetic Enhancement in Loessic Soils Estimated From Profiles of Rapidly Eroding Soils C. E. Geiss L. D. Urbano C. Munroe. Rates of Magnetic Enhancement. Two “end members” B. Maher – magnetic properties develop over short time periods (especially in loess)
E N D
Rates of Magnetic Enhancement in Loessic Soils Estimated From Profiles of Rapidly Eroding SoilsC. E. GeissL. D. UrbanoC. Munroe
Rates of Magnetic Enhancement Two “end members” • B. Maher – magnetic properties develop over short time periods (especially in loess) • M. Singer – California chronosequences show that magnetic enhancement might progress over very long time periods And many others in between or even farther out…
Simple 1D Magnetic Enhancement Model Rate of magnetic susceptibility enhancement decays exponentially with depth: (Anderson and Hallet, Quat.Res. 41, 1996) Model allows for lowering of soil surface By specifying an erosion rate
Is exponential decay appropriate ? Mount Calvary Cemetery, IA(and many others in the region) Deep , magnetically enhanced A-horizon Exponential decay model:accumulation of dust leads to thick A-horizons (e.g., Mason and Jacobs, Geology, 26, 1998)
Map courtesy of Isabel Iwachiw
C (m3/kg) T7
Additional Limitations mineral transformations mt only intermediate stage? (e.g., Oches, 1996, Barron and Torrent, 2003 etc.) equilibrium with climate in stable soils enhancement never ceases, does not reach stable equilibrium