Question

Marble belongs to__
A. Metamorphic Rocks
B. Sedimentary Rocks
C. Igneous Rocks
D. Volcanic Rock

Answer 1

Hint:
Metamorphic rocks, in a phase called metamorphism, which means change in form" emerge from the transformation of existing rock forms. Heat and pressure are exposed to the initial rock, causing profound physical or chemical changes.

Complete answer:
Marble is a metamorphic rock that develops when the heat and pressure of metamorphism are exposed to limestone. It consists mainly of the calcite mineral (CaCO3) and commonly includes other minerals, such as minerals of clay, micas, quartz, pyrite, iron oxides, and graphite. The calcite in the limestone recrystallizes under the conditions of metamorphism to form a rock that is a mass of interlocking calcite crystals. When dolostone is subjected to heat and pressure, a related rock, dolomite marble, is formed.

At convergent plate boundaries, most marble types are exposed to regional metamorphism in large areas of the Earth's crust. Some marble also forms when a hot magma body heats adjacent limestone or dolostone through contact metamorphism.

In wide deposits that can be hundreds of feet thick and geographically vast, marble occurs. This makes it possible to extract it economically on a wide scale, with some mines and quarries generating millions of tonnes per year.

Hence, the correct answer is option A.

Note:
Metamorphic rocks make up a large part of the crust of the earth and form 12 percent of the surface of the earth. By texture and by chemical and mineral assemblage, they are graded. They can be formed simply by being deep under the surface of the Earth, subjected to high temperatures and the great pressure above it by the rock layers.