BOUNDARIES AND INTERACTIONS OF SPHERES

The chief feature that distinguishes the earth from the other planets in the distribution of earth into various zones of spheres. They consist of the biosphere (which comprises living elements), the cryosphere (or related to ice), the hydrosphere (the element of water) and the atmosphere (the envelope of the planet). One of five spheres that impact the planet is the lithosphere. All of these spheres deeply converge with the entire natural world. For example, a bundle of these spheres are required for the formation of the soil. All these systems overlap and additionally are interconnected with each other. Any alteration in one sphere has a great influence on the other.

THE FIVE SPHERES THAT INTERACT WITH EACH OTHER

The earth consists of five spheres or systems that are described as follows:

Geosphere:

• The first sphere/system referred to as the geosphere, includes the surface and interior of the theEarth, which are composed of rocks.

Hydrosphere:

• The sites present at the earth’s surface are distributed with huge stretches of water bodies called the hydrosphere.

Lithosphere:

• 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.

Biosphere:

• 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. 

Atmosphere:

The atmosphere is a thin envelope formed by gases that extends to a height of about 1600km above the surface of the earth reaching the edge of space. Numerous complex chemical, thermodynamic, and fluid dynamics processes take place here. The composition of the atmosphere of Earth is a large percentage of nitrogen (78%), 21% oxygen, and one percent other gases.

Cryosphere: 

• The fifth system/sphere of the earth is composed of ice present in large quantities located at the poles and other places, making up  the cryosphere.

WHAT IS LITHOSPHERE?

The word lithosphere comes from the Greek word ‘lithos’ which means rocky. The rocky outermost segment of the earth/terrestrial type planet/natural satellite. It is referred to as the Lithosphere. It comprises the topmost portion of the mantle layer and frangible crust. The mantle shows an elastic behaviour on time scales. It is also called the rigid and the coolest segment of the earth. 

• The phenomenon of tectonic activity is quite an evident feature related to the lithosphere belonging to the earth.
• At the site of mid-ocean ridges, The layer of lithosphere becomes the thinnest. The mid-ocean ridges are the location of tearing apart tectonic plates from each other. 
• The lithospheric layer has a layer of the atmosphere above it and the asthenosphere above it. Simply the lithosphere is sandwiched between the layers of the atmosphere and the 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.
• The two categories of the lithosphere are- 

• Oceanic lithosphere: It is a bit dense. The oceanic lithosphere comprises the oceanic crust, which forms the floor of the sea. 
• Continental lithosphere

OCEANIC LITHOSPHERE 

• Oceanic lithosphere chiefly includes the mafic crust and peridotite or the ultramafic mantle. It is comparatively denser than its other counterpart, the continental lithosphere. 

• During its early age, the oceanic lithosphere is not thick in comparison with the crust but gets thick with age. 
• The reason behind the thickening is because of the phenomenon of ‘conductive cooling’. It involves the conversion of the high-temperature asthenosphere into the lithosphere. The resultant is the thickening of the oceanic lithosphere with age.

CONTINENTAL LITHOSPHERE

The range of thickness of the continental lithosphere varies from approximately 40 kilometres/ 25 miles to 280 kilometres/ 170 miles. The site Moho discontinuity marks the division between the crust and the upper mantle based on variation in chemical composition here. 

CONCLUSION

The earth system is sustainable and differentiating from others based on the presence of various spheres on planet earth. The word lithosphere comes from the Greek word ‘lithos’ which means rocky. The rocky outermost segment of the earth/terrestrial type planet/natural satellite. It is referred to as the Lithosphere. It comprises the topmost portion of the mantle layer and frangible crust. A seismograph is also called a seismometer. It is a device that helps to record and detect the phenomenon of earthquakes. A seismograph instrument consists of the following: a fixed base, a piece of mass attached to the base, a medium for recording, for example, a magnetic tape, paper etc.