Horizon: Soil greasiness in a Watauga soil series
Greasiness is the tactile response to a shear force by thumb and forefinger. It is a characteristic that is especially common to soils with significant amounts of platy minerals, generally mica. The property is due to the alignment of plates along the shear plane upon failure. It imparts the feel of a “greasy” residue to the skin.
If the specimen has a high content of mica, a sheen is often observed along the shear planes. The degree of greasiness is estimated by the relative ease with which the material shears. At failure, the specimen does not change suddenly to fluid. Greasiness is not defined by the amount of free water expressed but how a soil material responds to a manual test. It is a field observation assessment that helps to interpret soil behavior.
The Watauga series consists of very deep, well drained soils on gently sloping to very steep ridges and side slopes of the Southern Blue Ridge (MLRA 130B). Slope ranges from 2 to 50 percent. They formed in residuum that is affected by soil creep in the upper part, and is weathered from high-grade metamorphic rocks that are high in mica content such as mica gneiss and mica schist. Mean annual air temperature is about 52 degrees F., and mean annual precipitation is about 52 inches near the type location.
For more information about these soils, visit;
www.researchgate.net/publication/363254375_Report_of_the_...
For more information about describing and sampling soils, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/field...
or Chapter 3 of the Soil Survey manual:
www.nrcs.usda.gov/sites/default/files/2022-09/The-Soil-Su...
For additional information on "How to Use the Field Book for Describing and Sampling Soils" (video reference), visit:
www.youtube.com/watch?v=e_hQaXV7MpM
For additional information about soil classification using USDA-NRCS Soil Taxonomy, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/keys-...
or;
www.nrcs.usda.gov/resources/guides-and-instructions/soil-...
Horizon: Soil greasiness in a Watauga soil series
Greasiness is the tactile response to a shear force by thumb and forefinger. It is a characteristic that is especially common to soils with significant amounts of platy minerals, generally mica. The property is due to the alignment of plates along the shear plane upon failure. It imparts the feel of a “greasy” residue to the skin.
If the specimen has a high content of mica, a sheen is often observed along the shear planes. The degree of greasiness is estimated by the relative ease with which the material shears. At failure, the specimen does not change suddenly to fluid. Greasiness is not defined by the amount of free water expressed but how a soil material responds to a manual test. It is a field observation assessment that helps to interpret soil behavior.
The Watauga series consists of very deep, well drained soils on gently sloping to very steep ridges and side slopes of the Southern Blue Ridge (MLRA 130B). Slope ranges from 2 to 50 percent. They formed in residuum that is affected by soil creep in the upper part, and is weathered from high-grade metamorphic rocks that are high in mica content such as mica gneiss and mica schist. Mean annual air temperature is about 52 degrees F., and mean annual precipitation is about 52 inches near the type location.
For more information about these soils, visit;
www.researchgate.net/publication/363254375_Report_of_the_...
For more information about describing and sampling soils, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/field...
or Chapter 3 of the Soil Survey manual:
www.nrcs.usda.gov/sites/default/files/2022-09/The-Soil-Su...
For additional information on "How to Use the Field Book for Describing and Sampling Soils" (video reference), visit:
www.youtube.com/watch?v=e_hQaXV7MpM
For additional information about soil classification using USDA-NRCS Soil Taxonomy, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/keys-...
or;
www.nrcs.usda.gov/resources/guides-and-instructions/soil-...