How to distinguish sandstone and mudstone
Sandstone: composed of quartz grains (sand), stable in structure, usually pale brown or red, mainly containing silicon, calcium, clay, and ferric oxide. The rock consists of two parts: clastic and interstitial. In addition to quartz, feldspar, dolomite, heavy minerals, cuttings, etc.. The interstitial material comprises two components of the cement and the clastic complex. Common cements are siliceous and carbonate cements; the miscellaneous component is mainly a finer clay or silty sand that is deposited at the same time. The composition and structure of interstitial materials reflect the geological environment and physical and chemical conditions of sandstone formation. Sandstone can be divided into three categories: quartz sandstone, feldspar sandstone and lithic sandstone. Sand and sandstone are the main reservoirs of petroleum, natural gas and groundwater. Sand and sandstone can be used as abrasives, glass raw materials and building stone materials.
The main difference between them is that the particle size is different from that of clay mineral and cement and sand.The structure of argillaceous rock and sandstone is a sedimentary rock composed of fine particles.
Mudstone: mineral composition is complex, mainly composed of clay minerals (such as water mica, kaolinite, montmorillonite), followed by detrital minerals (quartz, feldspar, mica etc.), epigenetic minerals (such as epidote, chlorite) and iron manganese and organic matter. The texture is soft and the degree of consolidation is weaker than that of the shale. Common types are:Calcareous mudstone. It contains the right amount of calcium carbonate, which is often found in continental red rocks and marine and lacustrine facies.Ferruginous mudstone. Containing more iron minerals, such as hematite, limonite, goethite, etc., more common in red rock.Siliceous mudstone. The content of SiO2 is high, and it contains no or very little iron and carbonate, and is often associated with iron rock, siliceous rock and manganese facies. The mudstone has the properties of water absorption, bond and fire resistance, and can be used for making brick, brick, ceramics and other industries.
