Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Clastic rock
Summary
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus, chunks, and smaller grains of rock broken off other rocks by physical weathering. Geologists use the term clastic to refer to sedimentary rocks and particles in sediment transport, whether in suspension or as bed load, and in sediment deposits.
Clastic sedimentary rocks are rocks composed predominantly of broken pieces or clasts of older weathered and eroded rocks. Clastic sediments or sedimentary rocks are classified based on grain size, clast and cementing material (matrix) composition, and texture. The classification factors are often useful in determining a sample's environment of deposition. An example of clastic environment would be a river system in which the full range of grains being transported by the moving water consist of pieces eroded from solid rock upstream.
Grain size varies from clay in shales and claystones; through silt in siltstones; sand in sandstones; and gravel, cobble, to boulder sized fragments in conglomerates and breccias. The Krumbein phi (φ) scale numerically orders these terms in a logarithmic size scale.
Siliciclastic rocks are clastic noncarbonate rocks that are composed almost exclusively of silicon, either as forms of quartz or as silicates.
The composition of siliciclastic sedimentary rocks includes the chemical and mineralogical components of the framework as well as the cementing material that make up these rocks. Boggs divides them into four categories; major minerals, accessory minerals, rock fragments, and chemical sediments.
Major minerals can be categorized into subdivisions based on their resistance to chemical decomposition. Those that possess a great resistance to decomposition are categorized as stable, while those that do not are considered less stable. The most common stable mineral in siliciclastic sedimentary rocks is quartz (SiO2). Quartz makes up approximately 65 percent of framework grains present in sandstones and about 30 percent of minerals in the average shale.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Ontological neighbourhood
Related courses (3)
CIVIL-211: Geology
Les ingénieurs civils exercent leurs activités en constante interaction avec le sous-sol.
Le cours de géologie donne aux étudiants les bases en Géosciences nécessaires à une ingénierie bien intégrée d
CIVIL-308: Rock mechanics
Les étudiants comprennent le comportement mécanique de la roche intacte, des joints et des massifs rocheux et savent déterminer les facteurs influençant un projet. Ils savent utiliser les méthodes app
CIVIL-403: Geology for construction and environment
Détermination des roches principales, physique des écoulements souterrains en rapport avec les ouvrages, relations entre milieu géologique et construit.
Determination of the main rocks, physics of un
Related lectures (3)
Indices for River Assessment and Classification
Explores the assessment and classification of streams using ecological indices and emphasizes the importance of protecting and restoring river systems.
Bed Shapes and Flow Resistance
Explores the influence of bed shapes on flow resistance in rivers, covering dunes, ripples, benches, and background shapes.
Groundwater: Hydraulic Processes
Explores the significance of groundwater, aquifers, and flow equations in hydraulic processes.
Related publications (95)
Related people (24)
Related units (5)
Related concepts (30)
Glauconite
Glauconite is an iron potassium phyllosilicate (mica group) mineral of characteristic green color which is very friable and has very low weathering resistance. It crystallizes with a monoclinic geometry. Its name is derived from the Greek glaucos (γλαυκός) meaning 'bluish green', referring to the common blue-green color of the mineral; its sheen (mica glimmer) and blue-green color. Its color ranges from olive green, black green to bluish green, and yellowish on exposed surfaces due to oxidation.
Pebble
A pebble is a clast of rock with a particle size of based on the Udden-Wentworth scale of sedimentology. Pebbles are generally considered larger than granules ( in diameter) and smaller than cobbles ( in diameter). A rock made predominantly of pebbles is termed a conglomerate. Pebble tools are among the earliest known man-made artifacts, dating from the Palaeolithic period of human history. A beach composed chiefly of surface pebbles is commonly termed a shingle beach.
Siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeability and porosity is relatively low, siltstone is sometimes a tight gas reservoir rock, an unconventional reservoir for natural gas that requires hydraulic fracturing for economic gas production. Siltstone was prized in ancient Egypt for manufacturing statuary and cosmetic palettes.