The difference between brown red mudstone and brown red shale
Different ways of forming:Argillaceous sandstone: mainly formed by the flow of water and sediment in the riverbed;Shale: mainly formed by the deposition of clay and compaction by a certain temperature and pressure.
Different chemical composition:Argillaceous sandstone: argillaceous siltstone is mainly composed of silt, clay minerals and cement.Argillaceous siltstone, which means that the clay content is 50 - 25%, the silt content is as high as 70 - 50%.Shale: Shale in nature, the chemical content of the change is relatively large. In general, shale Si02 content fluctuated between 45%~80%, Al2O3 fluctuated between 12%-25%, Fe2O3 content fluctuated between 2%-10%, CaO content fluctuated between 0.2%-12%, the content of MgO in the 0.1%-5% range.
Different sedimentary environment:Argillaceous sandstone: often in water or in a relatively strong environment;Shale: often in still water.
Different structure:The structure of argillaceous siltstone is granular, the permeability is good, the particles are very small, and the sand diameter is about 1/16-1/250mm.The shale contains more organic matter and dispersed iron sulfide, the content of organic matter is up to 3 - 10%.
