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Shimada Seamount
Shimada Seamount is a seamount in the Pacific Ocean located southwest of Baja California Sur in Mexico. It is a shallow seamount, reaching a depth of below sea level and is a regular single-peaked mountain with a westerly spur and little relief otherwise. A platform lies at a depth of . Talus deposits surround the seamount at its base. The seafloor underneath Shimada is between 18 million and 21 million years old and lies at a depth of about ; other than abyssal hills at a distance of up to from Shimada, Shimada is isolated. Volcanic rocks taken from Shimada are considered to be icelandites. Most seamounts form at mid-ocean ridges, but hotspots and transform faults can also produce seamounts. These mechanisms cannot really explain the origin of Shimada Seamount, however; it may be part of a hotspot trace. Evidence from core samples around the seamount, the appearance of the summit area, and the presence of thin manganese crusts imply an age of about 10,000 years for some volcanic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seamount
A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to in height. They are defined by oceanographers as independent features that rise to at least above the seafloor, characteristically of conical form.IHO, 2008. Standardization of Undersea Feature Names: Guidelines Proposal form Terminology, 4th ed. International Hydrographic Organization and Intergovernmental Oceanographic Commission, Monaco. The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea. During their evolution over geologic time, the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface. After they have subsided and sunk below the sea surface such flat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seamounts Of The Pacific Ocean
A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to in height. They are defined by oceanographers as independent features that rise to at least above the seafloor, characteristically of conical form.IHO, 2008. Standardization of Undersea Feature Names: Guidelines Proposal form Terminology, 4th ed. International Hydrographic Organization and Intergovernmental Oceanographic Commission, Monaco. The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea. During their evolution over geologic time, the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface. After they have subsided and sunk below the sea surface such flat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vesteris Seamount
Vesteris Seamount, also known as Vesteris Bank, is a seamount in the Greenland Sea of the North Atlantic Ocean between Greenland and Norway. It lies north of Jan Mayen and rises from 41–43 million years old ocean crust. The reasons for the volcanic activity at Vesteris are unclear and may involve lithospheric processes. It is a volcano formed chiefly by basanitic rocks and has an erosion-flattened top. The seamount is covered by lava flows and subsidiary cones. The seamount started developing no earlier than 13 million years ago and eruptions continued until the Pleistocene/Holocene transition; there were a number of eruptions in the last 60,000 years. Whether there was Holocene activity 5,000–6,000 years ago or present-day hydrothermal activity is unclear. A variety of lifeforms are found both on Vesteris Seamount and within its rocks. Layers of sponges and bryozoans cover the upper parts of the seamount and form structures like mounds. This ecosystem has been compared to c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henderson Seamount
Henderson may refer to: People *Henderson (surname), description of the surname, and a list of people with the surname *Clan Henderson, a Scottish clan Places Argentina *Henderson, Buenos Aires Australia *Henderson, Western Australia Canada *Henderson Settlement, New Brunswick New Zealand *Henderson, New Zealand *Henderson (New Zealand electorate), former parliamentary electorate United States *Henderson, Colorado *Henderson, Georgia * Henderson, Houston County, Georgia *Henderson, Illinois *Henderson, Indiana * Henderson, Iowa *Henderson, Kentucky *Henderson, Louisiana *Henderson, Maryland * Henderson, Michigan *Henderson, Minnesota * Henderson, Missouri *Henderson, Nebraska *Henderson, Nevada *Henderson, New York, a town **Henderson (CDP), New York, a hamlet in the town *Henderson, North Carolina *Henderson, Tennessee *Henderson, Texas *Henderson, West Virginia *Henderson County (other) *Henderson Township (other) Geographic features * Henderson (crater), o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell M
A bell is a directly struck idiophone percussion instrument. Most bells have the shape of a hollow cup that when struck vibrates in a single strong strike tone, with its sides forming an efficient resonator. The strike may be made by an internal "clapper" or "uvula", an external hammer, or—in small bells—by a small loose sphere enclosed within the body of the bell (jingle bell). Bells are usually cast from bell metal (a type of bronze) for its resonant properties, but can also be made from other hard materials. This depends on the function. Some small bells such as ornamental bells or cowbells can be made from cast or pressed metal, glass or ceramic, but large bells such as a church, clock and tower bells are normally cast from bell metal. Bells intended to be heard over a wide area can range from a single bell hung in a turret or bell-gable, to a musical ensemble such as an English ring of bells, a carillon or a Russian zvon which are tuned to a common scale and installe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fisheries Science
Fisheries science is the academic discipline of managing and understanding fisheries. It is a multidisciplinary science, which draws on the disciplines of limnology, oceanography, freshwater biology, marine biology, meteorology, conservation, ecology, population dynamics, economics, statistics, decision analysis, management, and many others in an attempt to provide an integrated picture of fisheries. In some cases new disciplines have emerged, as in the case of bioeconomics and fisheries law. Because fisheries science is such an all-encompassing field, fisheries scientists often use methods from a broad array of academic disciplines. Over the most recent several decades, there have been declines in fish stocks (populations) in many regions along with increasing concern about the impact of intensive fishing on marine and freshwater biodiversity. Fisheries science is typically taught in a university setting, and can be the focus of an undergraduate, master's or Ph.D. program. Some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dredging
Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing dams, dikes, and other controls for streams and shorelines; and recovering valuable mineral deposits or marine life having commercial value. In all but a few situations the excavation is undertaken by a specialist floating plant, known as a dredger. Dredging is carried out in many different locations and for many different purposes, but the main objectives are usually to recover material of value or use, or to create a greater depth of water. Dredges have been classified as suction or mechanical. Dredging has significant environmental impacts: it can disturb marine sediments, leading to both short- and long-term water pollution, destroy important seabed ecosystems, and can release human-sourced toxins captured in the sediment. Description ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coral
Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which, when m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene has been identified with the current warm period, known as MIS 1. It is considered by some to be an interglacial period within the Pleistocene Epoch, called the Flandrian interglacial.Oxford University Press – Why Geography Matters: More Than Ever (book) – "Holocene Humanity" section https://books.google.com/books?id=7P0_sWIcBNsC The Holocene corresponds with the rapid proliferation, growth and impacts of the human species worldwide, including all of its written history, technological revolutions, development of major civilizations, and overall significant transition towards urban living in the present. The human impact on modern-era Earth and its ecosystems may be considered of global si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules Desnoye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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