Αποτελέσματα Αναζήτησης
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.
2 Φεβ 2023 · Crust. Temperature: 475 K (∼200°C) at the surface to 1300 K (∼1000°C) Thickness: 25 miles (32 km) for continental crust and 3-5 miles (8 km) for oceanic crust. Density: ∼ 2830 kg/m 3 at the continental crust and ∼ 3000 kg/m 3 at the oceanic crust. It is the outermost and thinnest layer of our planet and is least dense among all other layers.
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 crust is separated into two parts: the thin oceanic crust (between ∼3 and 10 km thick) with an approximate basaltic composition, and the thick continental crust (in average ∼35-40 km thick...
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 ...
24 Απρ 2024 · As we discussed in Chapter 10, oceanic crust is formed at sea-floor spreading ridges from magma generated by decompression melting of hot upward-moving mantle rock (Figure \(\PageIndex{3}\)). About 10% of the mantle rock melts under these conditions, producing mafic magma.
There are two main types of crust: oceanic and continental. Each has a different chemical composition and density. Oceanic crust underlies most of the world’s oceans, is typically about 5–7 kilometers (3–4 miles) thick, and is composed of mainly basalt.
