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About 6 km (4 miles)
- Oceanic crust is about 6 km (4 miles) thick. It is composed of several layers, not including the overlying sediment. The topmost layer, about 500 metres (1,650 feet) thick, includes lavas made of basalt (that is, rock material consisting largely of plagioclase [feldspar] and pyroxene).
www.britannica.com/science/oceanic-crust
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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.
Oceanic crust is significantly simpler than continental crust and generally can be divided in three layers. [8] According to mineral physics experiments, at lower mantle pressures, oceanic crust becomes denser than the surrounding mantle. [9] Layer 1 is on an average 0.4 km thick.
Jan 1, 2018 · Oceanic crust formed at MOR is primarily basaltic in composition and thin (~3–10 km thick) compared to continental crust that has an average thickness of 35–40 km and a roughly andesitic composition (Taylor and McLennan 1985; Rudnick 1995).
- Michael Perfit
- mperfit@ufl.edu
The continental crust ranges from 25 to 70 km thick and makes up a total of approximately 70 percent of Earth’s total crust volume, though it only covers about 40 percent of the planet’s surface area. The oceanic crust is much thinner, ranging from 5 to 10 km thick.
Dec 12, 2016 · We find that oceanic crust formed in the mid-Jurassic, about 170 million years ago, is 1.7 km thicker on average than crust produced along the present-day mid-ocean ridge system. If a...
- Harm J. A. Van Avendonk, Joshua K. Davis, Jennifer L. Harding, Lawrence A. Lawver
- 2017
On average, oceanic crust is 6–7 km thick and basaltic in composition as compared to the continental crust which averages 35–40 km thick and has a roughly andesitic composition.
Apr 24, 2024 · The oldest oceanic crust is around 280 Ma in the eastern Mediterranean, and the oldest parts of the open ocean are around 180 Ma on either side of the north Atlantic. It may be surprising, considering that parts of the continental crust are close to 4,000 Ma old, that the oldest sea floor is less than 300 Ma.
