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An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed, and often emplaced onto continental crustal rocks. The Greek word ὄφις, ophis (snake) is found in the name of ophiolites, because of the superficial texture of some of them. Serpentinite especially evokes a snakeskin.
Ophiolites are sequences of mafic to ultramafic rock generally believed to represent ancient oceanic lithosphere.They are distributed all across the world being all of them located at present or past orogenic belts, sites of mountain building processes.
Marine sediment, or ocean sediment, or seafloor sediment, are deposits of insoluble particles that have accumulated on the seafloor.These particles either 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, or they are biogenic deposits from marine organisms or from ...
Not only is land a major source of the ocean sediments, but organisms living within the ocean contribute, as well. The world's rivers transport the largest volume of suspended and dissolved loads of clay and silt to the sea, where they are deposited on ocean shelves. At the poles, glaciers and floating ice drop deposits directly to the sea floor.
However, ocean currents also flow thousands of meters below the surface. These deep-ocean currents are driven by differences in the water's density, which is controlled by temperature (thermo) and salinity (haline). This process is known as thermohaline circulation. In the Earth's polar regions ocean water gets very cold, forming sea ice.
Siliceous oozes accumulate over long timescales. In the open ocean, siliceous ooze accumulates at a rate of approximately 0.01 mol Si m −2 yr −1. [6] The fastest accumulation rates of siliceous ooze occur in the deep waters of the Southern Ocean (0.1 mol Si m −2 yr −1) where biogenic silica production and export is greatest. [7]
A stack or sea stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by wave erosion. [1] Stacks are formed over time by wind and water, processes of coastal geomorphology. [ 2 ]
An outcrop of the sheeted dyke complex of the Troodos ophiolite. The Troodos Ophiolite crops out in the central part of Cyprus in a northwest to southeast striking band. The lithospheric mantle crops out in the Troodos Mountains and in the Limassol Forest, Akapnou Forest, on the Akamas Peninsula and near Troullo.