Redoximorphic features: Relic redox concentrations or Plinthite (In Explore…)
Redoximorphic features (RMFs) consist of color patterns in a soil that are caused by loss (depletion) or gain (concentration) of pigment compared to the matrix color, formed by oxidation/reduction of iron and/or manganese coupled with their removal, translocation, or accrual; or a soil matrix color controlled by the presence of iron.
These color separations are used by soil scientists to document the presence of an active water table, both epi- and endo- saturation. However, changes in color may be an indication of a much older environment in which the features formed, not current saturation and reduction processes or as residual color inherited from the parent material.
One technique that helps determine if the feature is contemporary is the sharpness of the feature boundary. A color transition that is gradual or diffuse is commonly associated with contemporary aquic conditions. Transitions that are clear or sharp and more distinct are generally associated with relic or ancient soil environments. In addition, if the concentrations are relic, they tend to exhibit brittleness, although plinthite is commonly brittle even when present in a contemporary aquic regime.
A key distinction of plinthite is that it irreversibly hardens upon exposure to repeated wetting and drying, especially when directly exposed to rain and sun forming cemented materials (nodules, plates, concretions, or eventually ironstone). In situ, these iron concentrations range from noncemented to indurated.
The red redox concentrations in this image are potentially plinthite. They have a very firm rupture resistance, could be removed as a discrete body, and exhibited progressive hardening in the surrounding exposed road cuts.
The photo is from a depth of about 1.5 to 3 meters:
www.flickr.com/photos/jakelley/53416095121/in/dateposted-...
Hardened soil aggregates:
www.flickr.com/photos/jakelley/53414592606/in/album-72157...
For more information about a plinthic horizon, visit;
www.researchgate.net/publication/242649722_Rationale_for_...
or;
www.sciencedirect.com/science/article/pii/S00167061220043...
Redoximorphic features: Relic redox concentrations or Plinthite (In Explore…)
Redoximorphic features (RMFs) consist of color patterns in a soil that are caused by loss (depletion) or gain (concentration) of pigment compared to the matrix color, formed by oxidation/reduction of iron and/or manganese coupled with their removal, translocation, or accrual; or a soil matrix color controlled by the presence of iron.
These color separations are used by soil scientists to document the presence of an active water table, both epi- and endo- saturation. However, changes in color may be an indication of a much older environment in which the features formed, not current saturation and reduction processes or as residual color inherited from the parent material.
One technique that helps determine if the feature is contemporary is the sharpness of the feature boundary. A color transition that is gradual or diffuse is commonly associated with contemporary aquic conditions. Transitions that are clear or sharp and more distinct are generally associated with relic or ancient soil environments. In addition, if the concentrations are relic, they tend to exhibit brittleness, although plinthite is commonly brittle even when present in a contemporary aquic regime.
A key distinction of plinthite is that it irreversibly hardens upon exposure to repeated wetting and drying, especially when directly exposed to rain and sun forming cemented materials (nodules, plates, concretions, or eventually ironstone). In situ, these iron concentrations range from noncemented to indurated.
The red redox concentrations in this image are potentially plinthite. They have a very firm rupture resistance, could be removed as a discrete body, and exhibited progressive hardening in the surrounding exposed road cuts.
The photo is from a depth of about 1.5 to 3 meters:
www.flickr.com/photos/jakelley/53416095121/in/dateposted-...
Hardened soil aggregates:
www.flickr.com/photos/jakelley/53414592606/in/album-72157...
For more information about a plinthic horizon, visit;
www.researchgate.net/publication/242649722_Rationale_for_...
or;
www.sciencedirect.com/science/article/pii/S00167061220043...