Category: Engineering Geology Objective Questions

Engineering Geology Questions and Answers for Campus interviews on “Forms of Igneous Rocks – 02”.

1. The intrusive bodies in which injection of lava occurs without any influence of dip and strike is ______________
a) Concordant bodies
b) Discordant bodies
c) Non-cordant bodies
d) Uncomformities
Answer: b
Clarification: All those intrusive bodies that have been injected into the strata without being influenced by their structural disposition (dip and strike) and thus traverse across or oblique to the bedding planes etc. are grouped as discordant bodies.

2. The example not belonging to discordant body is ______________
a) Dykes
b) Volcanic necks
c) Bysmaliths
d) Batholiths
Answer: c
Clarification: Bysmalith is a type of laccolith which is again a type of concordant body and not a discordant body. The dykes, volcanic necks and batholiths are usually the widely studied types of discordant bodies.

3. Which discordant body is columnar or column shaped?
a) Dykes
b) Volcanic necks
c) Bysmaliths
d) Batholiths
Answer: a
Clarification: Dykes may be defined as columnar bodies of igneous rocks that cut across the bedding plane or uncoformities or cleavage planes and similar structures.

4. Texture shown by dykes is ______________
a) Equigranular
b) Directive
c) Intergrowth
d) All types of textures
Answer: d
Clarification: In composition, dykes are generally made up of hypabyssal rocks like dolerites, porphyrites and lamprophyres, showing all textures between glassy and phaneritic types.

5. Dykes tend to occur individually.
a) True
b) False
Answer: b
Clarification: Dykes generally tend to occur in groups or sets. Thus, the term dyke-set is used for a couple of parallel and closely spaced dykes.

6. When the vents of quiet volcanoes become sealed with intrusions it leads to ______________
a) Dyke
b) Batholith
c) Extrusion
d) Volcanic necks
Answer: d
Clarification: In some cases, vents of quiet volcanoes have become sealed with the intrusions. Such congealed intrusions are termed volcanic necks or volcanic plugs.

7. The bodies which show both concordant and discordant relations are ______________
a) Dykes
b) Sills
c) Batholiths
d) Phacoliths
Answer: c
Clarification: Batholiths are huge bodies of igneous masses that show both concordant and discordant relations with the country rocks.

8. What should be the area and depth respectively, for an igneous body to be called a batholith?
a) 100 square km and depth not traceable
b) 10 square km and depth up to 100km
c) Not traceable and depth 10 km
d) 50 km and depth 10 km
Answer: a
Clarification: The dimensions of batholiths vary considerably but it is generally agreed that to qualify as a batholith the igneous mass should be greater than 100 square kilometres in area and its depth should not be traceable.

9. What is the term used for a batholith when surface area is less than 100 km?
a) Dykes
b) Stock
c) Sock
d) Sillets
Answer: b
Clarification: When the surface area of batholith-like igneous mass is less than 100 km, it is commonly termed as stock. When such a stock has a roughly circular outline, it is further distinguished as a boss.

10. Majority of batholiths show which composition?
a) Felsitic
b) Granitic
c) Ophitic
d) Directive
Answer: b
Clarification: In composition, batholiths may be made of any type of igneous rock. They also exhibit many types of textures and structures. But as a matter of observation, majority of batholiths shows predominantly granitic composition, texture and structure.

11. Pick the wrong statement about granitization.
a) It is a set of processes rather than a single step
b) It involves already existing sedimentary and other rocks
c) It involves magmatic stage
d) It doesn’t actually require magmatic stage
Answer: c
Clarification: Granitization may be broadly described as a set of processes by which already existing sedimentary and other rocks are changed into granit-like without actually passing through a magmatic stage.

12. The volcanic sheets may vertical.
a) True
b) False
Answer: b
Clarification: The volcanic sheets may be horizontal or slightly inclined depending upon the original topography and subsequent geological history of the area.

Engineering Geology for Campus Interviews,

Basic Engineering Geology Questions and Answers on “Mineral Resources of India – 02”.

1. Asbestos is a fibrous variety of ___________
a) Chrysotile
b) Cristile
c) Christile
d) Christine
Answer: a
Clarification: The common asbestos is actually a fibrous variety of mineral Chrysotile-hydrous silicate of magnesium.

2. The amphibole varieties are found in which state?
a) Karnataka
b) Bihar
c) Orissa
d) Rajasthan
Answer: d
Clarification: The amphibole varieties anthophyllite and tremolite, are produced in Udaipur and Durgapur districts.

3. Which mineral is used in paints, rubber textiles?
a) Asbestos
b) Barytes
c) Corundum
d) Quartz
Answer: b
Clarification: The mineral Baryte finds use in paints, rubber textiles and also in oil well drilling muds besides in chemical industry.

4. Which state produces largest amount of barytes?
a) Kerala
b) Andhra Pradesh and Telangana
c) Karnataka
d) Orissa
Answer: b
Clarification: Andhra Pradesh is presently the largest producer of barytes in our country. The mineral occurs in limestones spread over districts of Kuddapah, Kurnool and Anantapur.

5. The pure variety of corundum is __________
a) Emerald and ruby
b) Ruby and Sapphire
c) Sapphire and diamond
d) Ruby and Coral
Answer: b
Clarification: A high grade natural abrasive- corundum. The mineral finds use in grinding wheels. Its pure varieties form gems- the ruby and sapphire.

6. Dolomite is not used for/as __________
a) Flux
b) Refractory material
c) Source in special cements
d) Precious gemstones
Answer: d
Clarification: Dolomite is carbonate rock of wide occurrence in India and elsewhere and also with wide applications as a flux in metallurgy, as a refractory material and as source material in special cement.

7. Which mineral is used in manufacture of Sorel cement?
a) Dolomite
b) Magnesite
c) Manganese
d) Iron
Answer: b
Clarification: Magnesite is one of the important refractory materials. Other uses of magnesite include in the manufacture of a special cement called Sorel cement, in chemical industry and also as a source of metal magnesium.

8. Mica is of which origin?
a) Igneous
b) Sedimentary
c) Metamorphic
d) Erosional
Answer: a
Clarification: The mica mineral is of an igneous origin and commonly occurs in pegmatites in the form of thick sheets and masses.

9. Gypsum commonly occurs as a mineral of which origin?
a) Primary
b) Secondary
c) Tertiary
d) Quarternary
Answer: b
Clarification: Gypsum commonly occurs as a mineral of secondary origin associated with other sedimentary formations in the form of intervening layers, stringers and extended beds.

10. The only producer of diamond in India is __________
a) Rajasthan
b) Madhya Pradesh
c) Bihar
d) Orissa
Answer: b
Clarification: In India, diamonds have been produced only in Madhya Pradesh from the well-known Panna diamond mines. Here the mineral occurs in volcanic pipes mixed with primary magmatic rocks and also from the conglomerate deposits around the hill.

To practice basic questions and answers on all areas of Engineering Geology,

Engineering Geology Multiple Choice Questions on “Types of Dams – 02”.

1. How many types of arch dams are present?
a) 1
b) 3
c) 4
d) 2
Answer: d
Clarification: Two main types of arch dams are: The constant radius arch dam and the variable radius dam.

2. The type of arch dam in which upstream face is vertical is __________
a) Constant radius arch dam
b) Variable radius arch dam
c) Vertical arch dam
d) Inclined arch dam
Answer: a
Clarification: The constant radius arch dam is an arch dam in which the radius of curvature throughout the structure is constant and upstream face is vertical.

3. An arch dam having a curvature both in horizontal and vertical alignment is called __________
a) Constant radius arch dam
b) Variable radius dam
c) Cupola
d) Cipalo
Answer: c
Clarification: An arch dam having a curvature both in horizontal and vertical alignment is often called a cupola dam.

4. Pick the wrong statement about arch dams.
a) Arch dams are heavier compared to other types
b) Arch dams offer many advantages over other dams
c) Arch dams are quite thin walled compared to gravity dams
d) Arch dams are lighter in weight compared to other types
Answer: a
Clarification: In ideal situation, arch dams offer many advantages over other types of dams. Arch dams are quite thin walled compared to gravity dams and hence lighter in weight.

5. Arch dams are best suitable for which site?
a) Flat lands
b) Plateaus
c) Narrow valleys
d) Very wide valleys
Answer: c
Clarification: Arch dams are better suited for narrow valleys with strong and uniformly sloping walls or abutments.

6. The arch dam in India is situated in which state?
a) Karnataka
b) Gujarat
c) Kerala
d) Maharashtra
Answer: c
Clarification: The Idukki dam in Kerala is an important arch dam of our country.

7. The dam which generally is of trapezoidal shape is __________
a) Gravity dams
b) Arch dams
c) Cupola dams
d) Embankment dams
Answer: d
Clarification: Embankment dams include a variety of non-rigid structures which are built over wide valleys with varying foundation characteristics from easily available materials such as earth and rock fragments. These are generally of trapezoidal shape.

8. The dam which can be constructed even on glacial deposits is __________
a) Gravity dams
b) Arch dams
c) Embankment dams
d) Cupola dams
Answer: c
Clarification: The main advantage of the embankment dams is that they can be constructed on weak foundations such as unconsolidated weak-river or glacial deposits.

9. The Hirakud dam in India is which type of dam?
a) Gravity dams
b) Arch dams
c) Cupola dams
d) Embankment dams
Answer: d
Clarification: The Hirakud dam in Orissa is one of the longest embankment dams of our country.

10. The compacted core is generally made of __________
a) Shale
b) Clay
c) Limestone
d) Coal
Answer: b
Clarification: An embankment dam is constructed as a homogeneous construction but very commonly, with a properly compacted core of impervious material such as clay.

11. An arch dam cannot be constructed at all when the valley is very wide.
a) True
b) False
Answer: b
Clarification: A combination of series of arch dams called Multiple Arch Dams is sometimes applied with an advantage when the valley is too wide for a single arch or gravity dam. Hence, arch dam can be constructed in a very wide valley too.

Engineering Geology Multiple Choice Questions on “Causes of Folding – 01”.

1. Pick the option which is not the cause of folding.
a) Folding due to tangential tension
b) Folding due to tangential compression
c) Folding due to intrusions
d) Folding due to differential compression
Answer: a
Clarification: The various causes of folding that are studied are, folding due to- tangential compression, intrusions and differential compression. Hence first option is not correct.

2. Bending or warping is studied under ___________
a) Tectonic folding
b) Non-tectonic folding
c) Volcanic folding
d) Intrusional folding
Answer: b
Clarification: Folding may be either due to tectonic causes or due to non-tectonic causes. The tectonic folding of the rocks is bending or warping of rocks due very conspicuously to superficial processes.

3. The cause of folding which does not occur due to the tangential stresses is ___________
a) Flexural folding
b) Flexural creeping
c) Flowage folding
d) Shear folding
Answer: b
Clarification: Under the influence of tangential stresses, folding may develop in either of the three ways: flexural folding, flowage folding and shear folding.

4. How does the thickness of the layer affect flexural folding?
a) Thinner the layers, greater is the slip
b) Thicker the layers, lesser is the slip
c) Thicker the layers, greater is the slip
d) Has no effect
Answer: c
Clarification: Thickness of the layers and nature of the contact are important factors on which the amount of slip depends. Thicker the layer, greater is the slip.

5. Which are the rocks more prone to flexural slip?
a) Shale
b) Basalt
c) Soft clay
d) Limestone
Answer: d
Clarification: Types of the rocks involved: siltstones, sandstones and limestones are more prone to flexure slip folding compared to soft clays and shales.

6. In which cause of folding, the thickness of fold does not remain uniform?
a) Flexural folding
b) Shear folding
c) Flowage folding
d) Flexural tension
Answer: c
Clarification: During the compression due to flowage folding, the material of the involved layers behaves almost as a viscous or plastic mass and gets buckled up and deformed at varying rates suffering unequal distortion. In such cases the thickness of the resulting fold does not remain uniform.

7. Flowage folding occurs in which type of rocks?
a) Competent rocks
b) Incompetent rocks
c) Any rock
d) Sedimentary rock
Answer: b
Clarification: Flowage folding is the principal process of folding in incompetent or weaker, plastic type of rocks such as clays, shales, gypsum and rock salt etc.

8. How does the distance from hinge point affect displacement due to folding?
a) Greater the distance, larger is the displacement
b) Lesser the distance, larger is the displacement
c) Doesn’t depend on the distance from hinge point
d) Greater the distance, smaller is the displacement
Answer: a
Clarification: Distance from hinge point is also an important factor on which displacement of folding depends. Greater the distance from the hinge points, larger is the displacement.

9. Flexural folding is also called as “flexural-slip-folding”.
a) False
b) True
Answer: b
Clarification: Flexural folding is also distinguished as flexural-slip-folding in which the slip or movement of the strata involved takes place parallel to the bedding planes of the layers.

10. The process of folding which causes fracture in rocks initially is ___________
a) Flexural folding
b) Flowage folding
c) Shear folding
d) Intrusion folding
Answer: c
Clarification: In many cases, folding is attributed to shearing stresses rather than simple compression. It is assumed that in such a process, numerous closely spaced fractures develop in the rock at the first stage of the process.

11. Pick the wrong statement. The converging plates maybe ___________
a) Two continental plates
b) A continental plate and an oceanic plate
c) A continental plate and an island plate
d) Two oceanic plates
Answer: d
Clarification: The converging plates may be two continental plates, a continental plate and an oceanic plate or a continental plate and an island plate but not two oceanic plate.

12. The displacement at the hinge point is maximum.
a) True
b) False
Answer: b
Clarification: Greater the distance from the hinge points, larger is the displacement, so much that it may be negligible at the hinge point. Hence the statement above is not true.

Engineering Geology Multiple Choice Questions on “Origin of Joints and Engineering Considerations”.

1. The nature of sedimentary rock that can undergo some irregular jointing is ___________
a) Plastic in nature
b) Non-plastic in nature
c) Rich in moisture
d) Plastic in nature and rich in moisture
Answer: d
Clarification: Sedimentary rocks especially those of plastic nature and rich in moisture in the initial stage (clays, shales, limestones, dolomites etc.) undergo some contraction on drying up which might have resulted into irregular jointing.

2. Contraction or shrinkage is the cause of which joints?
a) Radial joints
b) Vertical joints
c) Sheet joints
d) Mural joints
Answer: b
Clarification: During the formation of igneous rocks, tensile forces are developed in them due to cooling and the force is strong enough to cause joints. Such contraction or shrinkage is generally, accepted to be the cause of the vertical type of joints in granites and the so well -known columnar joints of basalts and other effusive rocks.

3. A single theory is enough to explain origin of all types of joints.
a) True
b) False
Answer: b
Clarification: Joints are caused in different rocks due to different reasons. No single theory can explain origin of all types of joints.

4. The wide range of temperature which vary in arid climate is ___________
a) -10° to 100° C
b) 10° to 80° C
c) -50° to 60°C
d) 50° to 60° C
Answer: c
Clarification: Repeated expansion and contraction is characteristic of regions with dry hot (arid) climates where day and night temperatures on the one hand and summer and winter temperatures on the other hand vary within a very wide range of -50° to 60° C.

5. Removal of overburden causes ___________
a) Expansion
b) Contraction
c) Shrinkage
d) Rise
Answer: a
Clarification: Removal of overburden due to weathering or other processes of rock wasting may also cause expansion of the underlying rocks due to unloading. The previously loaded rocks get relaxed with the release of the forces.

6. Sheet joints in sedimentary rocks are attributed to ___________
a) Erosional loading
b) Erosional unloading
c) Weathering loading
d) Weathering unloading
Answer: b
Clarification: The sheet joints of sedimentary rocks and other rocks are attributed by many to the process of erosional unloading through geological ages.

7. What kind of impact do the joints have on activities of engineering?
a) Positive
b) Negative
c) No impact
d) Positive and negative
Answer: d
Clarification: Joints affect the properties of rocks both in a negative as well as positive manner with respect to the activities of a professional civil and mining engineer.

8. What is/are related to jointed rocks?
a) Earthquakes
b) Landslides
c) Slope failures
d) Landslides and slope failures
Answer: d
Clarification: Many landslides and slope failures are directly related to the jointed nature of the rocks. This is due to instability of rocks in hilly regions and the jointed rocks get easily lubricated in presence of moisture and start sliding or falling from their places.

9. First step of treatment of joints is ___________
a) Grouting
b) Filling with chemicals
c) Detailed investigation
d) Installing devices
Answer: c
Clarification: Treating the negative qualities of rocks due to joints will differ in different projects. The first requirement in all cases is, however, detailed investigations to establish full characteristics of the joints.

10. What has to be located during an investigation with great care?
a) Macro joints
b) Fissures
c) Micro joints
d) Macro joints and micro joints
Answer: c
Clarification: Great care has to be exercised in locating the presence, distribution patterns and magnitude of micro joints that are typical of many rocks. Such joints, if left unnoticed and untreated, may widen after the construction of the project and endanger its stability.

11. What is a positive effect of joints?
a) Instability in slopes
b) Groundwater
c) Oil reserves
d) Groundwater and oil reserves
Answer: d
Clarification: As regards the positive effects of joints in rocks, these are greatly sought after in the exploration for groundwater and oil reserves in a given area. Only a well-jointed and porous rock can form a good aquifer or a good oil and gas reservoir.

12. Mineralisation takes place in jointed rocks.
a) True
b) False
Answer: a
Clarification: Mineralisation with economically valuable minerals from hydrothermal solutions takes place in jointed rocks and fissures, which are formed due to the widening of joints.