Engineering Geology Multiple Choice Questions on “Important Sedimentary Rocks – 01”.
1. Breccia is formed by which process?
a) Mechanical
b) Chemical
c) Organic
d) Residual
Answer: a
Clarification: Breccia is a mechanically formed sedimentary rock classed as rudite. It consists of angular fragments of heterogeneous composition.
2. The type of Breccia which is also called crush-breccia is ____________
a) Basal Breccia
b) Faulted Breccia
c) Agglomeratic Breccia
d) Rudite Breccia
Answer: b
Clarification: Faults Breccia is also called crush-breccia. Such rocks are so named because they are made up of angular fragments that have been produced during the process of faulting.
3. The type of Breccia formed by sea water is called ____________
a) Basal Breccia
b) Faulted Breccia
c) Agglomeratic Breccia
d) Rudite Breccia
Answer: a
Clarification: This rock is formed by the sea waters advancing over a coastal region covered with fragments of chert and other similar rocks.
4. Conglomerates belong to which group of sedimentary rocks?
a) Rudaceous rocks
b) Argillaceous rocks
c) Arenaceous rocks
d) Any group
Answer: a
Clarification: Conglomerates are sedimentary rocks of clastic nature and also belong to rudaceous group.
5. Conglomerates consist of which shaped fragments mostly?
a) Angular
b) Sub-angular
c) Rounded
d) Edged
Answer: c
Clarification: The conglomerates consist mostly of rounded fragments of various sizes but generally above 2 mm, cemented together in clayey or ferruginous or mixed matrix.
6. Which among the following is not a type of conglomerate?
a) Basal
b) Glacial
c) Volcanic
d) Faulted
Answer: d
Clarification: Sometimes the conglomerates are distinguished on the basis of source of the gravels, as: Basal, glacial and volcanic conglomerates.
7. The sedimentary rock which is arenaceous in nature is ____________
a) Conglomerate
b) Sandstone
c) Breccia
d) Shale
Answer: b
Clarification: Sandstones are mechanically formed sedimentary rocks of arenaceous group. These are mostly composed of sand grade particles that have been compacted and consolidated together in the form of beds in basins sedimentation.
8. Which is the dominant mineral in sandstone?
a) Mica
b) Diamond
c) Quartz
d) Felspar
Answer: c
Clarification: Quartz is the most common mineral making the sandstones. In fact some varieties of sandstones are made entirely of quartz.
9. The texture of sandstone is ____________
a) Fine-medium
b) Medium-coarse
c) Coarse
d) Fine-coarse
Answer: a
Clarification: Sandstones are, in general, medium to fine-medium grained in texture. The component grains show a great variation in their size, shape and arrangement in different varieties.
10. The colour of sandstone not found commonly is ____________
a) Blue
b) Red
c) Brown
d) White
Answer: a
Clarification: Sandstones naturally occur in a variety of colours: red, brown, grey and white being the most common colours. The colour of sandstone depends on its composition, especially the nature of the cementing material.