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The upper mantle of Earth is a very thick layer of rock inside the planet, which begins just beneath the crust (at about 10 km (6.2 mi) under the oceans and about 35 km (22 mi) under the continents) and ends at the top of the lower mantle at 670 km (420 mi).
The lithosphere is composed of both the crust and the portion of the upper mantle that behaves as a brittle, rigid solid. The asthenosphere is partially molten upper mantle material that behaves plastically and can flow.
Earth's upper mantle is divided into two major rheological layers: the rigid lithosphere comprising the uppermost mantle (the lithospheric mantle), and the more ductile asthenosphere, separated by the lithosphere-asthenosphere boundary.
1 Ιαν 2021 · The upper mantle is defined as that part of the mantle between the crust and the phase transition of γ–olivine to perovskite. The total mass of the upper mantle is 1.06 × 10 24 kg, about a quarter of the total mass of the mantle.
The Earth's upper mantle extends from below the crust to a depth of about 410 km. Here, we review the mineralogical and chemical composition of the upper mantle, especially with respect to the observed heterogeneities, both found in natural mantle rocks and in experiments.
29 Αυγ 2023 · In this Review, we discuss the effectiveness and challenges of using isotopic analyses of plume-generated rocks to infer mantle composition and to constrain geodynamic models.
Comparison of the chemical composition of the Earth's mantle by models based on extraterrestrial data to the Earth's unaltered upper mantle by Ringwood's pyrolite model and Nicholl's model, and to the partial fusion-partial crystallization model reveals convergence toward a similar over-all composition for the Earth's undepleted upper mantle.
