Anhydritic soil profile with Anhydritic soil material (75-145cm)
Anhydrite is a mineral—anhydrous calcium sulfate, CaSO4. Distinctly developed crystals are somewhat rare, the mineral usually presenting the form of cleavage masses. The hardness is 3.5 and the specific gravity 2.9. The color is white, sometimes greyish, bluish, or purple. When exposed to water, anhydrite readily transforms to the more commonly occurring gypsum, (CaSO4·2H2O) by the absorption of water. This transformation is reversible, with gypsum or calcium sulfate hemihydrate forming anhydrite by heating to ~200°C under normal atmospheric conditions. Anhydrite is commonly associated with calcite and halite.
www.researchgate.net/publication/259338144_Proposal_for_A...
The anhydritic horizon is a horizon in which anhydrite has accumulated through neoformation or transformation to a significant extent. It typically occurs as a subsurface horizon. It commonly occurs in conjunction with a salic horizon.
Identification of anhydrite (75-135 cm) is important when determining soil strength. Soils high in anhydrite exhibit fluidity and lack soil strength and load bearing capacity. Moisture content strongly influences soil’s consistence and a water table is commonly within the soil profile. The manner in which specimens of soil fail under increasing force ranges widely and usually is highly dependent on water state. To test for fluidity, a handful of soil material is squeezed in the hand. For moderately fluid materials after exerting full pressure, most flows through the fingers; a small residue remains in the palm of the hand.
For example, if some of the soil flows between the fingers with difficulty, the nvalue is between 0.7 and less than 1.0 (slightly fluid manner of failure class); if the soil flows easily between the fingers, the nvalue is 1 or more (moderately fluid or very fluid manner of failure class) depending on what remains in the palm of the hand.
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-...
For more information about soil classification in the UAE, visit:
vdocument.in/united-arab-emirates-keys-to-soil-taxonomy.h...
Anhydritic soil profile with Anhydritic soil material (75-145cm)
Anhydrite is a mineral—anhydrous calcium sulfate, CaSO4. Distinctly developed crystals are somewhat rare, the mineral usually presenting the form of cleavage masses. The hardness is 3.5 and the specific gravity 2.9. The color is white, sometimes greyish, bluish, or purple. When exposed to water, anhydrite readily transforms to the more commonly occurring gypsum, (CaSO4·2H2O) by the absorption of water. This transformation is reversible, with gypsum or calcium sulfate hemihydrate forming anhydrite by heating to ~200°C under normal atmospheric conditions. Anhydrite is commonly associated with calcite and halite.
www.researchgate.net/publication/259338144_Proposal_for_A...
The anhydritic horizon is a horizon in which anhydrite has accumulated through neoformation or transformation to a significant extent. It typically occurs as a subsurface horizon. It commonly occurs in conjunction with a salic horizon.
Identification of anhydrite (75-135 cm) is important when determining soil strength. Soils high in anhydrite exhibit fluidity and lack soil strength and load bearing capacity. Moisture content strongly influences soil’s consistence and a water table is commonly within the soil profile. The manner in which specimens of soil fail under increasing force ranges widely and usually is highly dependent on water state. To test for fluidity, a handful of soil material is squeezed in the hand. For moderately fluid materials after exerting full pressure, most flows through the fingers; a small residue remains in the palm of the hand.
For example, if some of the soil flows between the fingers with difficulty, the nvalue is between 0.7 and less than 1.0 (slightly fluid manner of failure class); if the soil flows easily between the fingers, the nvalue is 1 or more (moderately fluid or very fluid manner of failure class) depending on what remains in the palm of the hand.
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-...
For more information about soil classification in the UAE, visit:
vdocument.in/united-arab-emirates-keys-to-soil-taxonomy.h...