Question

The thickness of mantle is about
A. 2900 km
B. 2500 km
C. 2600 km
D. 2800 km

Answer 1

Hint: 1. The mantle forms 84% of Earth's total volume.
2. The mantle is the second layer of the earth.
3. The average temperature of the mantle is 3000 degree celsius.

Complete Answer:
- Composed of silicate rocky material with an average thickness of 2900 km, the mantle is situated between the Earth's crust and its upper core. The mantle is predominantly solid but it behaves like a viscous fluid due to the fact that temperatures are close to the melting point in this layer.
- In some places under the ocean the mantle is actually exposed. There are also a few places on land where mantle rock has been pushed to the surface by tectonic activity most notably the Tablelands region of Gros Morne National Park in Newfoundland and St. John's Island, Egypt.
- In terms of its constituent elements, the mantle is made up of 44.8% oxygen, 21.5% silicon and 22.8% magnesium. There's also iron,aluminium, calcium, and potassium. These elements are all bound together in the form of silicate rocks, all of which take the form of oxides.
- Activity in the mantle drives plate tectonics, contributing to volcanoes , seafloor spreading, earthquakes and oregon. (mountain building). The best access to the mantle comes in the form of lava that erupts at mid-ocean ridges.These ridges are at the middle of the ocean floor and generate new ocean crust. Samples of this lava show that it’s chemically mostly the same anywhere on the planet.

Hence the correct answer is Option A.

Note: 1. The mantle is the largest layer of the Earth.
2. The first attempt at mantle exploration (known as Project Mohale) achieved a penetration of approx 180 meters.
3. The mantle has 2 main parts- the upper mantle and the lower mantle.