Earth and Environment EASC 111
Igneous structures
An igneous rock is formed from magma, molten material deep inside the Earth.
Rocks are formed when this magma cools and solidifies. They may be composed of
different minerals depending on the temperature and pressure at which they were
formed. Extrusive igneous rocks are those that form when magma reaches the Earth's
surface. Intrusive igneous rocks are those that form when magma solidifies beneath
the surface of the Earth. We understand about intrusive igneous activity from the
study of old, and now solidified, magma bodies exposed by the erosion. The
intrusive or extrusive igneous rock bodies can occur in a variety of forms.
Concurrent Body
A concave surface is where two surfaces meet at right angles. A concave surface is
formed when two planes intersect at a right angle. This type of body forms when
magma rises from below the earth's crust and erupts onto the surface.
, Discordant Body
Discordant bodies form when magma erupts from beneath the surface and then cools
into solid rock. They are usually seen as large masses of hard rock that protrude
above the surrounding terrain.
Volcanic Plume
Volcanic plumes are hot gases that rise from volcanoes. They can be seen rising from
the ground and reaching great heights before dissipating.
Fissure Vent
Fissures venting lava rock is a common occurrence in volcanic areas. The lava flows
down the fissures and covers the landscape.
Batholith
Batholith is the most massive intrusive of all igneous bodies (means depth, stone).
They appear as massive linear structures hundreds of kilometres long and up to 100
kilometres wide. Batholiths are plutonic igneous rock masses that form the core of
mountains, such as the Ladakh batholith and the Mt Abu batholith. Batholiths are
always composed of granitic (felsic) and intermediate rock types, and they are
commonly referred to as granite batholiths. They form at a depth below the Earth's
surface and are only revealed after the overlying cover of the rock masses is
removed. They have no discernible floor but steep walls. They are typically
composed of quartz, feldspar, plagioclase, pyroxene, amphibole, biotite, magnetite,
ilmenite, titanite, and zircon. Batholiths are formed from the accumulation of lava
flows that solidify into massive blocks. This causes the batholith to rise above sea
Igneous structures
An igneous rock is formed from magma, molten material deep inside the Earth.
Rocks are formed when this magma cools and solidifies. They may be composed of
different minerals depending on the temperature and pressure at which they were
formed. Extrusive igneous rocks are those that form when magma reaches the Earth's
surface. Intrusive igneous rocks are those that form when magma solidifies beneath
the surface of the Earth. We understand about intrusive igneous activity from the
study of old, and now solidified, magma bodies exposed by the erosion. The
intrusive or extrusive igneous rock bodies can occur in a variety of forms.
Concurrent Body
A concave surface is where two surfaces meet at right angles. A concave surface is
formed when two planes intersect at a right angle. This type of body forms when
magma rises from below the earth's crust and erupts onto the surface.
, Discordant Body
Discordant bodies form when magma erupts from beneath the surface and then cools
into solid rock. They are usually seen as large masses of hard rock that protrude
above the surrounding terrain.
Volcanic Plume
Volcanic plumes are hot gases that rise from volcanoes. They can be seen rising from
the ground and reaching great heights before dissipating.
Fissure Vent
Fissures venting lava rock is a common occurrence in volcanic areas. The lava flows
down the fissures and covers the landscape.
Batholith
Batholith is the most massive intrusive of all igneous bodies (means depth, stone).
They appear as massive linear structures hundreds of kilometres long and up to 100
kilometres wide. Batholiths are plutonic igneous rock masses that form the core of
mountains, such as the Ladakh batholith and the Mt Abu batholith. Batholiths are
always composed of granitic (felsic) and intermediate rock types, and they are
commonly referred to as granite batholiths. They form at a depth below the Earth's
surface and are only revealed after the overlying cover of the rock masses is
removed. They have no discernible floor but steep walls. They are typically
composed of quartz, feldspar, plagioclase, pyroxene, amphibole, biotite, magnetite,
ilmenite, titanite, and zircon. Batholiths are formed from the accumulation of lava
flows that solidify into massive blocks. This causes the batholith to rise above sea
