Question

Which of the following rocks is different from the remaining three on the basis of its mode of origin?
A. Limestone
B. Sandstone
C. Shale
D. Marble

Answer 1

Hint: It is a metamorphic rock. It has been extensively used in the creation of one of the most popular monuments of the Mughal age. It is popularly used for sculpture and in construction of buildings.

Complete Answer:
Rocks are of various types. One way of classifying rocks is on the basis of their origin or how they are formed. Depending on its origin, rocks can be of three types- Igneous, Sedimentary and Metamorphic rocks. Sedimentary rocks are formed when moving water carries the fragmented pieces of rocks and soil and deposit them in layers. These layers gradually harden and turn into rocks due to the pressure and heat of overlying layers. Igneous rocks are formed due to the cooling of lava and magma. When cooled, they form very hard rocks. When either Igneous or Sedimentary rocks get transformed into a different form due to the effect of heat and/or pressure, Metamorphic rocks are formed.

Let us now see which kinds of rocks the given options are-
A. Limestone is an example of carbonate sedimentary rock.

B. Sandstone is also a type of clastic sedimentary rock.

C. Shale is a type of clastic sedimentary rock.

D. Marble is a kind of metamorphic rock. Since the rest of the options are sedimentary rocks and marble is the only metamorphic rock, this is the correct option.

Therefore, the correct answer is Option D.

Note: Marble is formed when Limestone undergoes metamorphosis. Sedimentary rocks are generally very soft rocks. They have bands or linear patterns in them due to their formation in layers. Metamorphic rocks are hard rocks and are much denser than the other kinds of rocks.