It is not possible to know about the earth’s interior by direct observations because
of its huge size and the changing nature of its internal composition. Through mining
and drilling operations we have been able to observe the earth’s interior directly
only up to a depth of few kilometers. The rapid increase in temperature below the
earth’s surface is mainly responsible for setting a limit to direct observation inside
the earth. The temperature in the earth’s interior is so high that it can even melt any
tool used for drilling. This fact also restricts deep drilling, thus causing hindrance to
direct observation of the materials of the earth’s interior .The huge size of the earth and increasing temperature with depth has set a limit to direct observation of the earth’s interior.
STRUCTURE OF THE EARTH’S INTERIOR
of its huge size and the changing nature of its internal composition. Through mining
and drilling operations we have been able to observe the earth’s interior directly
only up to a depth of few kilometers. The rapid increase in temperature below the
earth’s surface is mainly responsible for setting a limit to direct observation inside
the earth. The temperature in the earth’s interior is so high that it can even melt any
tool used for drilling. This fact also restricts deep drilling, thus causing hindrance to
direct observation of the materials of the earth’s interior .The huge size of the earth and increasing temperature with depth has set a limit to direct observation of the earth’s interior.
STRUCTURE OF THE EARTH’S INTERIOR
The above diagram shows the concentric layers of the earth’s interior.
The innermost layer surrounding the earth’s centre is called core, which is
about 3500 kms in radius. Core is the most dense layer of the earth with its density
range from 9.5 to 14.5 and sometimes even higher. It is composed mainly of the
iron and nickel thus commonly known as Nife. (Nickel+Ferrum). Core consists
of two sub-layers. The inner one is solid (C2 of fig. 2.1) and the outer one is semiliquid
(C1 of fig. 2.1). The layer surrounding the core is known as mantle, a rock
shell about 2900 kms thick and is composed of basic silicates. Major constituent
elements of mantle are magnesium and silicon, hence, this layer is termed as Sima
(Silica+Magnesium). The density of this layer varies from 3.3 to 5.7. Mantle is
surrounded by the outermost layer of the earth, known as lithosphere and its density
varies from 2.70 to 2.95. Major constituent elements of lithosphere are silica
(Si) and aluminium (Al), thus this layer is termed as Sial (Silica+Aluminium). The
outermost part of the lithosphere in known as crust, normally about 8 to 40 kms
thick.
The innermost layer surrounding the earth’s centre is called core, which is
about 3500 kms in radius. Core is the most dense layer of the earth with its density
range from 9.5 to 14.5 and sometimes even higher. It is composed mainly of the
iron and nickel thus commonly known as Nife. (Nickel+Ferrum). Core consists
of two sub-layers. The inner one is solid (C2 of fig. 2.1) and the outer one is semiliquid
(C1 of fig. 2.1). The layer surrounding the core is known as mantle, a rock
shell about 2900 kms thick and is composed of basic silicates. Major constituent
elements of mantle are magnesium and silicon, hence, this layer is termed as Sima
(Silica+Magnesium). The density of this layer varies from 3.3 to 5.7. Mantle is
surrounded by the outermost layer of the earth, known as lithosphere and its density
varies from 2.70 to 2.95. Major constituent elements of lithosphere are silica
(Si) and aluminium (Al), thus this layer is termed as Sial (Silica+Aluminium). The
outermost part of the lithosphere in known as crust, normally about 8 to 40 kms
thick.
No comments:
Post a Comment