Engineering Geology Multiple Choice Questions on “Different Rock as Aquifers”.
1. Which sedimentary rock is told to be the best kind of formation for groundwater?
a) Sandstone
b) Shale
c) Gravel
d) Limestone
Answer: c
Clarification: Gravels are classed among the best kind of formations to yield groundwater. But these too show a great variation in their water bearing properties depending on the degree of assortment, packing and cementing of the grains.
2. The rock which shows great variation in water yielding capacity is __________
a) Sandstone
b) Granite
c) Coal
d) Marble
Answer: a
Clarification: Sandstones are the sedimentary rocks that show great variation in their water yielding capacity which is chiefly controlled by their texture and nature of the cementing material.
3. What is rated next to the gravels as water yielding materials?
a) Sandstone
b) Sands
c) Granite
d) Limestone
Answer: b
Clarification: Sand beds or loosely packed sandstones are rated next to gravels as water yielding materials.
4. The porosity range of limestone is __________
a) 50 to 75%
b) 20 to 50%
c) 10 to 40%
d) 1 to 20%
Answer: d
Clarification: The porosity of limestones varies from 1 to 20%. Hydraulic conductivity in highly karsted limestones may be as high as 100 m/day or even more, to be classed among the extremely permeable rocks.
5. What are the qualities required for glacial deposits to make good aquifers?
a) Uniform size and rounded nature
b) Non-uniform and angular nature
c) Uniform size and angular nature
d) Non-uniform and rounded nature
Answer: a
Clarification: When the glacial deposits are made up of sediments of uniform size and rounded nature, they present with best quality. When sufficiently thick and extensive, these may be depended as reliable groundwater reservoirs.
6. Igneous rocks are intrusive in nature.
a) True
b) False
Answer: b
Clarification: Igneous rocks are either intrusive or extrusive in nature. The intrusive igneous rocks are dense in texture with all the component minerals very closely crystallized. The extrusive rocks exhibit great variation in their water bearing properties.
7. The igneous rock rich in cavities is __________
a) Granite
b) Basalt
c) Gabbro
d) Dolomite
Answer: b
Clarification: Basic volcanic rocks like basalts, are characterized by greater gas content and high mobility at the time of eruption.
8. When can a surface become porous and permeable or water bearing?
a) Weathered
b) Weathered and wet
c) Weathered and disintegrated
d) Disintegrated and wet
Answer: c
Clarification: In all igneous rocks, the surface zone when highly weathered and disintegrated may become quite porous and permeable and hence water-bearing.
9. The fractured and fissured metamorphic rock is similar in character to which igneous rock?
a) Volcanic
b) Plutonic
c) Hypabyssal
d) Dykes
Answer: b
Clarification: The profusely fractured and fissured metamorphic rocks exhibit similar characters of that of the igneous rocks of plutonic nature. Groundwater will be found in the fractured zones without lateral and vertical continuity.
10. Metamorphic rocks that are inherently fractured and foliated may prove to be good aquifers.
a) True
b) False
Answer: a
Clarification: Metamorphic rocks that are inherently fractured and foliated such as slates, schists, phyllites and often gneisses, may prove exceptionally good aquifers, in a broader sense.