GeologyGeology () is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure.
Marine sedimentMarine sediment, or ocean sediment, or seafloor sediment, are deposits of insoluble particles that have accumulated on the seafloor. These particles have their origins in soil and rocks and have been transported from the land to the sea, mainly by rivers but also by dust carried by wind and by the flow of glaciers into the sea. Additional deposits come from marine organisms and chemical precipitation in seawater, as well as from underwater volcanoes and meteorite debris.
Minimum railway curve radiusThe minimum railway curve radius is the shortest allowable design radius for the centerline of railway tracks under a particular set of conditions. It has an important bearing on construction costs and operating costs and, in combination with superelevation (difference in elevation of the two rails) in the case of train tracks, determines the maximum safe speed of a curve. The minimum radius of a curve is one parameter in the design of railway vehicles as well as trams; monorails and automated guideways are also subject to a minimum radius.
Lunar geologic timescaleThe lunar geological timescale (or selenological timescale) divides the history of Earth's Moon into five generally recognized periods: the Copernican, Eratosthenian, Imbrian (Late and Early epochs), Nectarian, and Pre-Nectarian. The boundaries of this time scale are related to large impact events that have modified the lunar surface, changes in crater formation through time, and the size-frequency distribution of craters superposed on geological units.
Flood mythA flood myth or a deluge myth is a myth in which a great flood, usually sent by a deity or deities, destroys civilization, often in an act of divine retribution. Parallels are often drawn between the flood waters of these myths and the primaeval waters which appear in certain creation myths, as the flood waters are described as a measure for the cleansing of humanity, in preparation for rebirth. Most flood myths also contain a culture hero, who "represents the human craving for life".
Poincaré metricIn mathematics, the Poincaré metric, named after Henri Poincaré, is the metric tensor describing a two-dimensional surface of constant negative curvature. It is the natural metric commonly used in a variety of calculations in hyperbolic geometry or Riemann surfaces. There are three equivalent representations commonly used in two-dimensional hyperbolic geometry. One is the Poincaré half-plane model, defining a model of hyperbolic space on the upper half-plane. The Poincaré disk model defines a model for hyperbolic space on the unit disk.
Flood basaltA flood basalt (or plateau basalt) is the result of a giant volcanic eruption or series of eruptions that covers large stretches of land or the ocean floor with basalt lava. Many flood basalts have been attributed to the onset of a hotspot reaching the surface of the earth via a mantle plume. Flood basalt provinces such as the Deccan Traps of India are often called traps, after the Swedish word trappa (meaning "staircase"), due to the characteristic stairstep geomorphology of many associated landscapes.
Genesis flood narrativeThe Genesis flood narrative (chapters 6–9 of the Book of Genesis) is a Hebrew flood myth. It tells of God's decision to return the universe to its pre-creation state of watery chaos and remake it through the microcosm of Noah's ark. The Book of Genesis was probably composed around the 5th century BCE, although some scholars believe that Primeval history (chapters 1–11), including the flood narrative, may have been composed and added as late as the 3rd century BCE.
Congo RiverThe Congo River (Nzâdi Kôngo, Fleuve Congo, Rio Congo), formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third largest river in the world by discharge volume, following the Amazon and the Ganges rivers. It is also the world's deepest recorded river, with measured depths of around . The Congo-Lualaba-Chambeshi River system has an overall length of , which makes it the world's ninth-longest river.
Congo BasinThe Congo Basin (Bassin du Congo) is the sedimentary basin of the Congo River. The Congo Basin is located in Central Africa, in a region known as west equatorial Africa. The Congo Basin region is sometimes known simply as the Congo. It contains some of the largest tropical rainforests in the world and is an important source of water used in agriculture and energy generation. The rainforest in the Congo Basin is the largest rainforest in Africa and second only to the Amazon rainforest in size, with 300 million hectares compared to the 800 million hectares in the Amazon.
