Q. Consider the following statements:
1. Earth’s outer core and inner core are in solid and liquid form respectively.
2. Asthenosphere is the upper part of core.
Which of the above given statement is/are correct?
The inner core is solid, the outer core is liquid, and the mantle is solid/plastic. This is due to the relative melting points of the different layers (nickel–iron core, silicate crust and mantle) and the increase in temperature and pressure as depth increases. At the surface, the nickel-iron alloys and silicates are cool enough to be solid. In the upper mantle, the silicates are generally solid but localized regions of melt exist, leading to limited viscosity.
The mantle extends from Moho’s discontinuity to a depth of 2,900 km. The upper portion of the mantle is called asthenosphere. The word astheno means weak. It is considered to be extending upto 400 km.It is the main source of magma that findsits way to the surface during volcanic eruptions.
Source: NCERT
