Shale

Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering or bedding less than one centimeter in thickness, called fissility.Mudstones, on the other hand, are similar in composition but do not show the fissility.

Historical mining terminology

Before the mid 19th century, the terms slate, shale and schist were not sharply distinguished. In the context of underground coal mining, shale was frequently referred to as slate well into the 20th century.

Texture

Shale typically exhibits varying degrees of fissility breaking into thin layers, often splintery and usually parallel to the otherwise indistinguishable bedding plane because of parallel orientation of clay mineral flakes. Non-fissile rocks of similar composition but made of particles smaller than 0.06 mm are described as mudstones (1/3 to 2/3 silt particles) or claystone (less than 1/3 silt). Rocks with similar particle sizes but with less clay (greater than 2/3 silt) and therefore grittier are siltstones. Shale is the most common sedimentary rock.

Shale (disambiguation)

Shale may refer to:

Shalë, Albania

Shalë is a former municipality in the Shkodër County, northwestern Albania. At the 2015 local government reform it became a subdivision of the municipality Shkodër. The population at the 2011 census was 1,804. Its name comes from the Shala tribe which lives in the area. The municipal unit covers the upper course of the river Shalë, and part of the Prokletije mountains. There are eleven small mountain villages in the municipality: Breg-Lumi, Abat, Nicaj-Shalë, Lekaj, Vuksanaj, Pecaj, Theth, Ndërhysaj, Gimaj, Nen-Mavriq, Mekshaj, and Lotaj.

Gallery

Theth valley

Theth valley

Theth valley

Theth valley

References

External links