Context:
As per new study, a new enigmatic layer called “E prime layer” at the outermost part of Earth’s core is a result of surface water penetrating deep into the planet.
Highlights of the study:
- Reason for new layer formation – “surface water penetrating deep into the planet”
- This alters the composition of the metallic liquid core’s outermost region proposes.
- It suggests that tectonic plates carrying surface water have transported it deep into the Earth over billions of years.
- This subducted water reacts chemically with core materials under high pressure.
- This led to the formation of a hydrogen-rich, silicon depleted layer at the outer core.
- Silica crystals generated ascend and blend into the mantle.
- These modifications in the liquid metallic layer could potentially result in reduced density and altered seismic characteristics.
- Applications of the study:
- Discovery enhances our comprehension of Earth’s internal mechanisms.
- The transformed layer in the core holds significant implications for the interconnected geochemical processes linking surface water cycles with the deep metallic core.
Layers of Earth:
- Crust: This is the outside layer of the earth and is made of solid rock, mostly basalt and granite.
- Mantle: It lies below the crust and is up to 2900 km thick. It consists of hot, dense, iron and magnesium-rich solid rock.
- Core: It is the center of the earth and is made up of 2 parts: the liquid outer core and solid inner core. The outer core is made of nickel, iron and molten rock.
Seismic discontinuities:
- Seismic discontinuities are the regions in the earth where seismic waves behave a lot different compared to the surrounding regions due to a marked change in physical or chemical properties.
- Sudden jumps in seismic velocities across a boundary are known as seismic discontinuities.
| Type of Discontinuity | Layers in between |
| Conrad Discontinuity | Upper Crust and Lower Crust |
| Mohorovicic (Moho) Discontinuity | Lower Crust and Upper Mantle |
| Repetti Discontinuity | Upper Mantle and Lower Mantle |
| Guttenberg Discontinuity | Lower Mantle and the Outer Core |
| Lehmann Discontinuity | Outer Core and Inner Core |
Source: Hindustan Times
Previous Year Question
In the structure of planet Earth, below the mantle, the core is mainly made up of which one of the following?
[UPSC Civil Services Exam – 2009 Prelims]
(a) Aluminium
(b) Chromium
(c) Iron
(d) Silicon
Answer: (c)
