- 2076 Asoj · 4 marks
Short note: Lutite
Short answer
Lutite is a fine-grained clastic sedimentary rock composed of clay- and silt-size particles (<0.06 mm). It is soft, low strength, swells when wet, low permeability, and is a poor foundation rock but a good seal. Used for bricks, tiles; metamorphoses to slate, phyllite, schist.
Write a short note on lutite.
Lutite (argillaceous rock) is a fine-grained clastic sedimentary rock composed of clay- and silt-size particles (<0.06 mm). Lutites are formed by deposition of mud in quiet water (lakes, lagoons, deep sea) and later compaction.
- Types: clay, mudstone, siltstone, claystone and shale. Shale is the fissile variety.
- Texture and structure: very fine, pelitic; laminated or thinly bedded; may be fissile.
- Minerals: clay minerals (kaolinite, illite, montmorillonite), fine quartz and mica.
- Properties: soft, low strength, plastic when wet, absorbs water, swells and slakes, low permeability.
- Engineering significance: poor foundation rock, unstable in slopes and tunnels, weak when wet; however, being impermeable, it is a good seal for reservoirs and dam abutments. Used for bricks, tiles, pottery and cement.
- On metamorphism, lutite changes to slate, phyllite and schist.
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