Old Biosphere, Lithosphere, Hydrosphere

The five zones of the Earth can be divided into the Geosphere, cryosphere, hydrosphere, biosphere, and atmosphere. The earth’s zones are overlapping and also interrelated to each other thus giving sustainability and a distinguishing feature from other planets. The interior of the earth is differentiated based on chemical and mechanical properties. 

Rheological/ mechanical division talks about the liquid phase of the rocks. Subdivision of the Earth’s layer based on rheology is the lithosphere, asthenosphere, mesosphere, outer core, and inner core. However, chemical differentiation is segmented into crust, mantle, outer core, and inner core.

BRIEFING – BIOSPHERE, LITHOSPHERE, HYDROSPHERE 

The limited segment of the planet earth that is a support for the living elements consists of one of the systems referred to as the biosphere. The rocky outermost segment of the earth/terrestrial type planet/natural satellite. It is referred to as the Lithosphere. The word lithosphere is a derivation from the Greek word called ‘lithos’ inferring rocky.  It comprises the topmost portion of the mantle layer and frangible crust. Thirdly, the sites present at the earth’s surface are distributed with huge stretches of water bodies called the hydrosphere. 

THE INTERIOR OF THE EARTH

The interior of the earth is the distribution of concentric layers that divides the earth’s sphere, except the earth’s atmosphere and the earth’s hydrosphere. The outermost zone of the earth’s spherical layer is called the crust. It is a silicate rich solid layer. Secondly, a high viscosity zone of the asthenosphere and solid layer of the mantle. The outer core is present in a liquid phase. The liquidity and flow are what leads to the generation of the magnetic field of the earth. The inner core is also solid. The following are key points based on scientific data that characterise the interior of the earth- 

• Observations done on the topographical features

• Bathymetry (the study of the floor of ocean/lake/river floor)

• The rock when observed in the outcrop. 

• Utilising the samples of the volcanic activity or volcanos, that are obtained at the surface from larger depths

• Seismic waves passing through the layers of the earth analysis is utilised.

• Values obtained from the magnetic and gravitational fields of Earth. 

• Experimentations were done with the aid of crystalline solids at different pressure and temperature conditions

• Characteristic features of deep layers of the earth.

LAYERS OF THE EARTH

The layers of earth can be classified into two divisions, based on the concept of mechanical and chemical properties. Mechanical properties include the study i.e. rheology. The following are the two classifications:

MECHANICAL CLASSIFICATION

• Lithosphere

• Asthenosphere

• Mesospheric mantle

• Outer core

• The inner core.

CHEMICAL CLASSIFICATION

Chemically, the following are the Earth’s layers. 

• Crust

• The upper segment of the mantle

• The lower segment of the mantle

• Outer core

• Inner core

LITHOSPHERE

The word lithosphere is a derivation from the Greek word called ‘lithos’ inferring rocky. The lithospheric layer is the rocky outermost segment of the earth/terrestrial type planet/natural satellite. 

ASTHENOSPHERE

• The asthenosphere consists of rocks in molten rock making it more viscous and thick.

• The lithosphere-asthenosphere boundary (LAB) is the site of the transformation of the solid lithosphere into the asthenosphere. The LAB is inconsistent in its depth, it alters from location to location.

MANTLE

The mantle is the earth’s layer lying below the crust and forms 84% of the volume of earth. The  Mohorovicic Discontinuity marks the initiation of the mantle, also called the Moho. At this site, seismic wave velocity intensifies. The Moho refers to contrast in density ranging from slightly dense crust to the denser mantle layer. The mantle shows properties resembling the plastic material. At high temperature and pressure ranges, it becomes deformable at timescales in geology.

CRUST

It is the thinnest layer of earth. Its thickness alters based on the location of the earth. The oceanic crust extends approximately 5-10 kilometres and continental mountain segments extend up to a thickness of 30-45 kilometres. In comparison, the oceanic crust is denser than its counterpart- continental crust. Hence, it ‘floats’ lower in the layer of the mantle than the continental crust.

OUTER CORE

The outer core is present in the liquid phase. It consists of an enormous iron distribution. it is below the layer of the mantle. It is a high-temperature zone ranging from 4,030 to 5,730 degrees Celsius. 

INNER CORE

It is present at the centermost location of Earth and has quite similarities to the outer core. The differentiation of the distinguishing feature between the outer core and inner core is based on density. 

CONCLUSION

The layers of Earth are a medium for the geophysicists and geologists to dwell deeper on the concepts of how the formation of the earth took place, the layers that comprise other planets, the medium of incurring the Earth’s resources etc. The interior of the earth is the distribution of concentric layers that divides the earth’s sphere, except the earth’s atmosphere and the earth’s hydrosphere. The dissection of the earth into various layers is based on the chemical and mechanical properties of every layer. The earth’s zones are interrelated to each other thus giving sustainability and a distinguishing feature from other planets.