31. A large volcanic collapse depression, more or less circular in outline or cirque like in form called:

(a) Calderas

(b) Fluidizing gas in a pyroclastic flow

(c) Phreatomagnetic eruptions

(d) Caldera collapse and foundation of crater

Answer: (a)

32. Extrusions of fluid basaltic flows from a central vent complex or from a fissure system can build a subdued volcano and are called:

(a) Cinder cone

(b) Plateau basalt

(c) Spatter

(d) Shield volcano

Answer: (d)

33. The incorporation of matter from wall rocks into magma to form a hybrid igneous rock, the processes is called:

(a) Fractional crystallization

(b) Magmatic segregation

(c) Assimilation

(d) Liquid immiscibility

Answer: (c)

34. The occurrence of similar mineral assemblage throughout rocks of a similar bulk chemical composition and exposed over a particular area of the metamorphic terrain is called:

(a) Metamorphic facies

(b) Metamorphic zone

(c) Metamorphism

(d) Retrograde Metamorphism

Answer: (b)

35. The joints run in a direction that lies between the strike and dip direction of the bed is:

(a) Strike joints

(b) Dip joints

(c) Oblique joints

(d) Bedding joints

Answer: (c)

36. The type of folding in which the competent or stronger beds are thrown into folds due to their sliding against each other under the influence of compression are:

(a) Flowage folding

(b) Shear folding

(c) Flexural folding

(d) Conjugate folding

Answer: (c)

37. The San Andres Fault of California which is extending to several hundred kilometers is an example of:

(a) Strike-slip fault

(b) Thrust fault

(c) Over thrust fault

(d) Peripheral fault

Answer: (a)

38. The most destructive, fearful and rare type of volcanic eruption is:

(a) Volcanian

(b) Strombolian

(c) Hawaiian

(d) Pelean

Answer: (d)

39. When the axis plunges directly down the dip of the axial plane; the fold is known as:

(a) Plunging fold

(b) Reclined fold

(c) Flexure fold

(d) Periclinal fold

Answer: (b)

40. If the surface of erosion is deposited by younger sediments and residual soil but a sharp contact may be lacking, then it is:

(a) Blended unconformity

(b) Disconformity

(c) Local unconformity

(d) Angular unconformity

Answer: (a)