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Which statement best describes the inner

core?
A. It is at the very center of the earth and consists of metal.
B. It is the layer responsible for plate tectonics.
C. It is the molten middle layer.
D. It has two layers, continental and oceanic.

User Jstuardo
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1 Answer

3 votes

The right matches are:

1. The inner core is matched with F) the solid iron.

The inner core, or seed, is the solid part in the center of the Earth. It is a ball of 1,220 kilometers in radius located in the center of the outer core (liquid). It is composed of an alloy of iron and nickel, as well as lighter elements. The boundary between the outer core and the inner core is called Lehmann's discontinuity, or ICB (for inner core boundary).

2. The outer core is matched with G) very dense liquid of iron and sulfur

The outer core is the liquid part of the Earth's core, an intermediate layer located above the solid seed (inner core) and below the Earth's mantle. Like the seed, the core is a metal alloy, consisting mainly of iron and nickel. The liquid of the outer core is animated by rapid convective movements that induce a dynamo effect at the origin of the Earth's magnetic field.

3. The lower mantle is matched with C) layer just outside of the outer core

The lower mantle is sometimes called the "mesosphere". It extends from 700 to 2900 km deep.

The lower mantle is responsible for a particular phenomenon: hot spots. Hot spots are volcanoes that are not born at the border of two tectonic plates, unlike ordinary volcanoes, but in the middle of these plates. They occur when the god chief and deceased is irregular. The lava from these volcanoes is more gaseous and comes from the depths of the mantle (hence the lower mantle), which allows to deduce the shape of the lava at this level.

4. The upper mantle is matched with B) made of large plates that move

The top of the mantle and the crust form the lithosphere, which can reach 300 km below the continents (since the oceanic crust is much thinner). The part of the lithosphere that is not the crust (hence the top of the upper mantle) is very brittle (which allows it to move). From 200 to 700 km deep, we find the "asthenosphere", which is the plastic part of the upper mantle.

5. The crust layer is matched with D) thin, rigid surface of Earth

The earth's crust is the superficial and solid part of the material from which the Earth is made. This is the upper part of the lithosphere (which constitutes the tectonic plates).

The boundary between the Earth's crust and the upper mantle is the Mohorovicic discontinuity.

The earth's crust exists in two radically different "varieties", the continental crust, of predominantly granitoidal petrological composition, and the oceanic crust of essentially basaltic nature.

6. The lithosphere is matched with E) layer that includes the asthenosphere

The lithosphere is the rigid terrestrial envelope of the Earth's surface. It includes the earth's crust and part of the upper mantle.

It is divided into a number of tectonic plates, also called lithospheric plates.

The lithosphere, relatively rigid on time scales of the order of 1 to 10 Ma, rests on the asthenosphere, solid but ductile, more easily deformable because it consists of rocks under physico-mechanical conditions (pressure, temperature, therefore speed increased deformation), leading to a relatively low viscosity.

7. The asthenosphere is matched with A) platic portion of the upper mantle of the Earth.

The asthenosphere (from the Greek asthenos, without resistance) is the ductile part of the upper terrestrial mantle. It extends from the lithosphere to the lower mantle for 700 kilometers.

This concept emerged in the late 1960s with the plate tectonics revolution and the mesosphere concept. The asthenosphere is between the lithosphere and the mesosphere.

User Sandro Wiggers
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8.1k points
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