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Cyclic Steps
Cyclic steps are rhythmic bedforms associated with Froude super-critical flow instability. They are a type of sediment wave, and are created when supercritical sediment-laden water (turbidity currents) travels downslope through sediment beds. Each ‘step’ has a steep drop, and together they tend to migrate upstream. On the ocean floor, this phenomenon was first shown to be possible in 2006, although it was observed in open-channel flows over a decade earlier. Geological features appearing to be submarine cyclic steps have been detected in the northern lowlands of Mars in the Aeolis Mensae region, providing evidence of an ancient Martian ocean. Formation There are many parameters which govern the formation of cyclic steps; bed slope, bed porosity, erosion resistance, sediment concentration, and flow rate all play a role. Tilting flumes can be used to create cyclic steps in subaerial laboratory conditions, provided the Froude number is high enough. If the Froude number is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monterey Cyclic Steps Profile View
Monterey (; es, Monterrey; Ohlone: ) is a city located in Monterey County on the southern edge of Monterey Bay on the U.S. state of California's Central Coast. Founded on June 3, 1770, it functioned as the capital of Alta California under both Spain (1804–1821) and Mexico (1822–1846). During this period, Monterey hosted California's first theater, public building, public library, publicly-funded school, printing-press, and newspaper. It was originally the only port of entry for all taxable goods in California. In 1846, during the Mexican–American War of 1846–1848, the United States Flag was raised over the Customs House. After Mexico ceded California to the U.S. at the end of the war, Monterey hosted California's first constitutional convention in 1849. The city occupies a land area of and the city hall is at above sea level. The 2020 census recorded a population of 30,218. Monterey and the surrounding area have attracted artists since the late 19th-century, and m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antidune
An antidune is a bedform found in fluvial and other channeled environments. Antidunes occur in supercritical flow, meaning that the Froude number is greater than 1.0 or the flow velocity exceeds the wave velocity; this is also known as upper flow regime. In antidunes, sediment is deposited on the upstream (stoss) side and eroded from the downstream (lee) side, opposite lower flow regime bedforms. As a result, antidunes migrate in an upstream direction, counter to the current flow. Antidunes are called in-phase bedforms, meaning that the water surface elevation mimics the bed elevation; this is due to the supercritical flow regime. Antidune bedforms evolve rapidly, growing in amplitude as they migrate upstream. The resultant wave at the water's surface also increases in amplitude. When that wave becomes unstable, breaks and washes downstream, much of the antidune bedform may be destroyed. Formation Antidunes are typically found in fluvial environments in shallow areas with a high f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coastal And Oceanic Landforms
The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in natural ecosystems, often home to a wide range of biodiversity. On land, they harbor important ecosystems such as freshwater or estuarine wetlands, which are important for bird populations and other terrestrial animals. In wave-protected areas they harbor saltmarshes, mangroves or seagrasses, all of which can provide nursery habitat for finfish, shellfish, and other aquatic species. Rocky shores are usually found along exposed coasts and provide habitat for a wide range of sessile animals (e.g. mussels, starfish, barnacles) and various kinds of seaweeds. Along tropical coasts with clear, nutrient-poor water, coral reefs can often be found between depths of . According to a United Nations atlas, 44% of all people live within 5 km (3.3mi) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentology
Sedimentology encompasses the study of modern sediments such as sand, silt, and clay, and the processes that result in their formation (erosion and weathering), transport, deposition and diagenesis. Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary structures. Sedimentary rocks cover up to 75% of the Earth's surface, record much of the Earth's history, and harbor the fossil record. Sedimentology is closely linked to stratigraphy, the study of the physical and temporal relationships between rock layers or strata. The premise that the processes affecting the earth today are the same as in the past is the basis for determining how sedimentary features in the rock record were formed. By comparing similar features today to features in the rock record—for example, by comparing modern sand dunes to dunes preserved in ancient aeolian sandstones—geologists reconstruct past environmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Katabatic Wind
A katabatic wind (named from the Greek word κατάβασις ''katabasis'', meaning "descending") is a drainage wind, a wind that carries high-density air from a higher elevation down a slope under the force of gravity. Such winds are sometimes also called fall winds; the spelling catabatic winds is also used. Katabatic winds can rush down elevated slopes at hurricane speeds, but most are not that intense and many are 10 knots (18 km/h) or less. Not all downslope winds are katabatic. For instance, winds such as the föhn and chinook are rain shadow winds where air driven upslope on the windward side of a mountain range drops its moisture and descends leeward drier and warmer. Examples of true katabatic winds include the bora in the Adriatic, the Bohemian Wind or ''Böhmwind'' in the Ore Mountains, the Santa Ana in southern California, the piteraq winds of Greenland, and the oroshi in Japan. Another example is "the Barber", an enhanced katabatic wind that blows over t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciolacustrine Deposits
Sediments deposited into lakes that have come from glaciers are called glaciolacustrine deposits. These lakes include ice margin lakes or other types formed from glacial erosion or deposition. Sediments in the bedload and suspended load are carried into lakes and deposited. The bedload is deposited at the lake margin while the suspended load is deposited all over the lake bed. Glaciolacustrine deposits commonly form varves, which are annually deposited layers of silt and clay, where silt is deposited during the summer, and clay during the winter. Bedload deposits Sediments carried in the bedload of a stream, mostly sands and gravels, are deposited in deltas that form at the edges of lakes. These deposits will only be found near the edges of the lake. Suspended deposits Sediments that are carried in the suspended load of a stream, commonly silts and clays, are transported into the lake in suspension or by currents along the lake floor. These are the principal deposits during the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monterey Canyon
Monterey Canyon, or Monterey Submarine Canyon, is a submarine canyon in Monterey Bay, California with steep canyon walls measuring a full 1 mile in height from bottom to top, which height/depth rivals the depth of the Grand Canyon itself. It is the largest such submarine canyon along the West coast of the North American continent, and was formed by the underwater erosion process known as turbidity current erosion. Many questions remain unresolved regarding the exact nature of its origins, and as such it is the subject of several ongoing geological and marine life studies being carried out by scientists stationed at the nearby Monterey Bay Aquarium Research Institute, the Moss Landing Marine Laboratories, and other oceanographic institutions. Monterey Canyon begins at Moss Landing, California, which is situated along the middle of the coast of Monterey Bay, and extends horizontally under the Pacific Ocean where it terminates at the Monterey Canyon submarine fan, reaching dept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monterey Cyclic Steps Birds Eye View
Monterey (; es, Monterrey; Ohlone: ) is a city located in Monterey County on the southern edge of Monterey Bay on the U.S. state of California's Central Coast. Founded on June 3, 1770, it functioned as the capital of Alta California under both Spain (1804–1821) and Mexico (1822–1846). During this period, Monterey hosted California's first theater, public building, public library, publicly-funded school, printing-press, and newspaper. It was originally the only port of entry for all taxable goods in California. In 1846, during the Mexican–American War of 1846–1848, the United States Flag was raised over the Customs House. After Mexico ceded California to the U.S. at the end of the war, Monterey hosted California's first constitutional convention in 1849. The city occupies a land area of and the city hall is at above sea level. The 2020 census recorded a population of 30,218. Monterey and the surrounding area have attracted artists since the late 19th-century, and m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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