USDA Texture Triangle
Definition
Ternary diagram that classifies soils by relative proportion of sand (2.0 to 0.05 mm), silt (0.05 to 0.002 mm) and clay (less than 0.002 mm) into 12 classes (sand, loamy sand, sandy loam, loam, silt loam, silt, clay loam, sandy clay loam, silty clay loam, sandy clay, silty clay, clay).
Related terms
- Density-Gradient Column
- Glass column filled with stepwise layers of liquids of decreasing density (commonly bromoform 2.89 g/cm3 and bromobenzene 1.50 g/cm3 mixed in known...
- Loss on Ignition (LOI)
- Weight loss after heating dried soil to 550 degrees Celsius. Approximates the organic matter content. A simple, cheap, high-yield discriminator in field...
- Munsell Soil Colour
- Standardised colour notation written as hue, value and chroma (e.g. 10YR 4/3 dark brown). Read by holding a moist soil sample against...
- Regur (Black Cotton Soil)
- Indian Vertisol formed on Deccan basalt. High in smectite (montmorillonite) clay, deep black colour, swells and shrinks dramatically with moisture. Major signature...
- Soil
- Weathered surface layer of earth made of mineral particles, organic matter (humus), water, air and living micro-organisms. The forensic interest is in...
- XRD
- X-ray diffraction. Identifies crystalline mineral phases (quartz, feldspar, kaolinite, montmorillonite, calcite) by their characteristic d-spacings via Bragg's law. The mineral assemblage is...
- XRF and ICP-MS
- Elemental techniques for the trace-metal fingerprint (Fe, Ti, Mn, Cr, Ni, V, rare earths). XRF (often EDXRF) is non-destructive; ICP-MS is destructive...
Explained in
- Dust and Soil: Nature, Types and Forensic ExaminationTernary diagram that classifies soils by relative proportion of sand (2.0 to 0.05 mm), silt (0.05 to 0.002 mm) and clay (less than 0.002 mm) into 12 classes (s...