Geography [1 Mark Question Answer]

Carbonaceous Sedimentary rocks.

Sedimentary rocks.

Intrusive igneous rocks.

Extrusive igneous rocks

The magma takes place in between the layers of rocks and hardens after cooling, which is called Sill.

Conical mountains and extensive lava plateaus.

Basic igneous rocks have higher percentage of oxides of denser elements and dark in colour, e.g. Basalt, dolerite etc.

Igneous rocks are formed by cooling of magma and these are crystalline rocks and full of mineral compounds.

The igneous rocks were the first to be formed. They form the basis of formation of other types of rocks. Thus, they are called primary rocks.

Three types of rocks are sedimentary, igneous and metamorphic rocks.

Igneous rocks are associated with volcanic activity, cooling of magma and mechanical weathering etc.

These are silicon, aluminium, iron, magnesium, calcium, potassium, sodium and nickel.

This is a mechanical Transformation in which texture of rocks is changed by crushing and rubbing processes associated with heat and compression created by mechanical action.

Limestone is converted to marble and shale is transformed to slate.

Metamorphic rocks are formed by complete change of texture of rocks through volcanism and diastrophism.

There are three main agents of deposition i.e., water, wind and ice, which mainly act as agents of change on the surface of earth for deposition of sediments.

Lithification is the process of turning loose rock material into hard rock through evaporation, compaction and cementation.

Sedimentary rocks are most widespread on the earth.

Sedimentary rocks are associated with fossil fuels due to fossils trapped in between layers of these rocks.

Igneous rocks are associated with ores of metals due to their origin by cooling magma resulting in crystalline rocks rich in mineral content.

Sedimentary rocks are called Secondary rocks or derived – rocks because they are derived by the denudation of other rocks.

The basis for the classification of rocks are their mineral composition, colour and texture.

Himalayan Region

Narmada Basin

Deccan Plateau

Gypsum

Clay

Basic igneous rocks

Acidic igneous rocks

Nife

SIAL

Carbonaceous rocks

Igneous rocks

SIMA

Crust

The term metamorphism means change of form. It may be physical or chemical or both.

Silicates are the most common rock forming minerals because they are most common minerals in the Earth’s crust.

Extrusive rocks generally have small crystals because in the formation of these rocks, the solidification of magma takes place at a slower rate.

Granite is very good example of a Plutonic rock.

Plutonic rocks are the igneous rocks which are formed as some depth in the earth’s crust, when a molten material gets solidified under pressure.

The dead sea abounds in chemically formed sedimentary rock because the evaporation of water from it is rapid.

Fossils are found in sedimentary rocks. Organic remains of plants and animals or their skeletal impressions are called fossils. Fossils help us in fixing the relative ages of rocks.

Dynamic metamorphism.

Slate

Rock salt

Conglomerate

Sill

Plutonic rocks

Mineral