Geophysical and structural evaluations of the Earth distinguish between compositional layers (crust, mantle, core) and mechanical zones (lithosphere, asthenosphere). Which of the following statements accurately characterizes the compositional and structural relationships between the continental crust, oceanic crust, and the underlying mantle zones?
- The continental crust (sial) is predominantly granitic and lighter than the continuous basaltic layer (sima), which forms the oceanic floor and rests above the plastic asthenosphere.Cevap
- BThe upper sialic crust is formed primarily through metamorphic recrystallization during sub-aerial weathering processes occurring at the Earth's surface.
- CThe downslope movement of loose lithospheric rock debris into ocean trenches under gravitational pull is classified as in-situ physical weathering.
- DThe continuous sima layer consists predominantly of sedimentary limestone formed through ocean deposition and chemical weathering of continental sial.
Cevap
The continental crust (sial) is predominantly granitic and lighter than the continuous basaltic layer (sima), which forms the oceanic floor and rests above the plastic asthenosphere.
The continental crust (sial) is rich in silica and aluminium, making it less dense and predominantly granitic. It sits upon the denser, continuous basaltic layer rich in silica and magnesium (sima), which underlies ocean basins and overlies the partially molten, ductile asthenosphere in the upper mantle.
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Anahtar Kavram
Earth's Internal Structure (Sial, Sima, Lithosphere, and Asthenosphere)
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