geomorphology & earth landforms section 2 Practice Questions Answers Test with Solutions & More Shortcuts

Answer: (a)

Answer: (a)

Block separation:

Rocks that have developed cracks and joints break off at these cracks. This process is more active on sedimentary rocks. In the case of sedimentary rock, cracks occur near the surface of the earth and rocks disintegrate into almost rectangular pieces.

Answer: (c)

Igneous rock is one of the three main rock types, the others being a sedimentary and metamorphic rock. In terms of modes of occurrence, igneous rocks can be either intrusive (plutonic), extrusive (volcanic) or hypabyssal.

Granite is an intrusive igneous rock that is formed from magma that cools and solidifies within the crust of a planet. They form the central cores of major mountain ranges.

Answer: (d)

Igneous rock (derived from the Latin word ignis meaning fire) is one of the three main rock types, the others being a sedimentary and metamorphic rock.

Igneous rock is formed through the cooling and solidification of magma or lava. Igneous rock may form with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.

This magma can be derived from partial melts of pre-existing rocks in either a planet’s mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition.

Granite is the best-known igneous rock. Many people recognize granite because it is the most common igneous rock found on Earth’s surface and because granite is used to make many objects that we encounter in daily life.

Answer: (b)

A rift valley is a linear-shaped lowland caused due to the fissure in the earth along which one side moves down with reference to the other. It is commonly seen between several highlands or mountain ranges created by the action of a geologic rift or fault.

A rift valley is formed on a divergent plate boundary, a crustal extension, a spreading apart of the surface.