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oceanic crust, the outermost layer of Earth’s lithosphere that is found under the oceans and formed at spreading centres on oceanic ridges, which occur at divergent plate boundaries. Oceanic crust is about 6 km (4 miles) thick. It is composed of several layers, not including the overlying sediment.
This chapter reviews the architecture of the oceanic crust, the geochemical processes by which it is created, as well as its major element, trace element, and isotopic composition. The principal focus is on the more readily sampled volcanic upper oceanic crust; the gabbroic lower crust is reviewed by Coogan (see Chapter 4.14).
1 Ιαν 2018 · Oceanic crust is the outermost solid layer of the lithospheric tectonic plates under the oceans that covers much of the Earth’s surface. It has a distinctive basaltic composition characterized by rocks that have relatively low concentrations of potassium and other highly incompatible trace elements (those typically excluded from minerals that ...
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust , composed of troctolite , gabbro and ultramafic cumulates .
The oceanic crust is thin, relatively young and uncomplicated compared to the continental crust, and chemically magnesium-rich compared to continental material. The oceanic crust is the product of partial melting of the mantle at the mid-ocean ridges: it is the cooled and crystallized melt fraction.
1 Νοε 2013 · Oceanic crust consists almost exclusively of extrusive basalt and its intrusive equivalents. This chapter focuses on the roughly 1.5-2. km thick 'volcanic layer' consisting of lava flows that...
1 Ιαν 2023 · Oceanic crust is the outer solid layer of the Earth beneath the oceans. This type of crust is 6–9 km thick, it is essentially basaltic (mafic) in composition and denser of the continental crust. It comprises three main layers (from top to bottom): Layer 1, a thin layer (typically less than 500 m thick) of deep-water unconsolidated carbonate ...
