Engineering Geology Multiple Choice Questions on “Structures of Sedimentary Rocks”.
1. The layered arrangement in sedimentary rocks is called ____________
a) Mud cracks
b) Stratification
c) Rain prints
d) Ripple marks
Answer: b
Clarification: By stratification is understood a layered arrangement in sedimentary rock. This may be developed very prominently and can be seen from a distance of miles or in other cases may have to be ascertained after close examination of the rock.
2. The structure most prevalent to clastic rocks is ____________
a) Nodular structure
b) Geode structure
c) Concretionary structure
d) Lamination
Answer: d
Clarification: The most prevalent structures of a clastic group of sedimentary rocks are the ones belonging to mechanical structure which are, stratification, lamination, cross beddings, rain prints etc.
3. Lamination is structure formed in which type of sedimentary rocks?
a) Fine grained
b) Medium grained
c) Coarse grained
d) Nothing in particular
Answer: a
Clarification: Lamination is a characteristic structure of fine-grained sedimentary rocks like clays and shales.
4. Each layer of a laminated structure of sedimentary rock is called ____________
a) Strata
b) Leaf
c) Lamina
d) Layer
Answer: c
Clarification: The individual layers of the laminated structure are called lamiae and are distinguished commonly on the basis of difference in colour.
5. Which among the following is not a type of false bedding?
a) Columnar
b) Tabular
c) Lenticular
d) Wedge shaped
Answer: a
Clarification: The common types of false bedding are, tabular, lenticular, wedge shaped. Columnar is not a type of false bedding.
6. The type of false bedding where top and bottom surfaces are parallel is ____________
a) Columnar
b) Tabular
c) Lenticular
d) Wedge shaped
Answer: b
Clarification: Tabular false bedding is a type of cross bedding in which the top and bottom surfaces of the deposit are essentially parallel, indicating its deposition in the same main channel.
7. Type of false bedding where the individual layers exist in well-defined sets of parallel layers is ____________
a) Columnar
b) Tabular
c) Lenticular
d) Wedge shaped
Answer: d
Clarification: In the case of wedge shaped cross bedding, the cross-bedding structure is highly complex: the individual layers exist in well-defined sets of parallel layers but these sets bear angular relationship to each other.
8. Type of bedding where sorting and arrangement has occurred based on grain size is ____________
a) Cross bedding
b) Lamination
c) Graded bedding
d) Mud cracks
Answer: c
Clarification: In some stratified rocks the component sediments in each layer appear to be characteristically sorted and arranged according to their grain size, the coarsest being placed at the bottom and the finest at the top.
9. Graded bedding occurs due to which phenomenon?
a) Wind settling
b) Sunlight
c) Gravitational settling
d) Loading
Answer: c
Clarification: Normally, perfectly graded beds are the result of sedimentation in bodies of standing water where factor of gravitative settling from a mixed load is predominant process.
10. Mud cracks are common in which type of sedimentary rocks?
a) Fine grained
b) Medium grained
c) Coarse grained
d) Not particular
Answer: a
Clarification: Mud cracks are common structural features of many fine-grained sedimentary rocks. The structure consists of polygonal or irregular cracks spread along the surface of an exposed sedimentary layer.
11. The bedding involving crater shaped depressions is ____________
a) Mud cracks
b) Rain prints
c) Ripple marks
d) Sun cracks
Answer: b
Clarification: Rain prints are irregular, small crater-shaped depressions seen on fine-grained dried sediments.
12. Which of the following does not provide evidence of shallow water environment?
a) Lamination
b) Rain prints
c) Ripple marks
d) Mud cracks
Answer: a
Clarification: The mud cracks, rain prints and ripple marks when encountered in sedimentary formations are taken as confirmatory evidence of the formation having been deposited in a shallow water environment.
13. Which structure resembles fish eggs?
a) Pisolitic
b) Felsitic
c) Oolitic
d) Granitic
Answer: c
Clarification: The Oolitic structure is the structure where the concretions are of the size of fish eggs; the rock appears as an assemblage of fish eggs.
14. Peanut structure is shown by ____________
a) Sandstone
b) Limestone
c) Shale
d) Breccia
Answer: b
Clarification: The pisolitic structure is another type of concretionary structure where the individual size of a concretion is like that of a peanut. Limestones and bauxite show both these structures.