Question

What is earth's lower mantle made of

Answer 1

Hint : We know that it is important to know the interior of the earth so that we can study the interior composition of the earth. This is only possible through mining and drilling operations and that too up to a few kilometers. The last one is the core. It is the innermost layer of the earth. The core comprises two layers namely the inner core and the outer core.

Complete Step By Step Answer:
The interior structure of the earth comprises different layers such as the lithosphere, Asthenosphere, Mesosphere, and Barysphere. The lithosphere can be defined as the outermost part of the earth. It is a rigid and rocky part. It lengthens up to $100$ Km inside the earth. The asthenosphere lies beneath the Lithosphere and it lengthens from $100\text{ }Km\text{ }to\text{ }700\text{ }Km$ inside the surface of the earth. The asthenosphere is a type of fragile or weak layer. The mesosphere is the third layer inside the earth. It comprises the lower mantle. After that comes the Barysphere. It is the last or hindmost layer inside the earth. It comprises the outer core and the inner core. The whole interior earth’s structure is divided into crust, mantle, and core. The crust comprises $1$ of the earth’s volume and $0.5$of the earth’s mass. The thickness of the crust is$8\text{ }\text{ }40\text{ }km$. The crust is made up of Silica and Aluminium. The composition of the interior of the earth changes according to environmental changes.
The inner core is a solid ball of mostly metal. It is solid because of the pressure of the rest of the Earth around it, even though it is at $5700K$ and should be liquid if it were at normal pressure. Its pressure is actually about $3,500,000$atmospheres.
Scientists have tested the density of the core by firing waves at it and measuring their reaction and found that actually a pure nickel-iron compound is more dense than the core, meaning that the core has lighter elements in it, probably carbon, oxygen or silicon.

Note :
Remember that the mantle accounts for $84$of the earth’s volume and $67$ of the earth’s mass. It is made up of silicon and magnesium. The core account’s for $15$ of earth’s volume and $32.5$of earth’s mass. The mantle is the interior portion beyond the crust. The thickness of the mantle is $2900\text{ }Km.$