COMPETITIVE EXAM MCQs SERIES of ENVIRONMENTAL SCIENCE for UGC-NET/JRF, SLET, ARS, GATE, and other entrance tests – Environmental Geosciences-Concept of Minerals & Rocks.
Syllabus Outline
- Composition, classification, and properties of minerals (e.g. chemical structure and physical characteristics).
- Types of rocks, detailing their formation and characteristics.
- Igneous Rocks (e.g. Intrusive Igneous Rocks: Granite, Diorite and Gabbro, Extrusive Igneous Rocks: Basalt, Andesite, and Rhyolite).
- Sedimentary Rocks (e.g. Clastic Sedimentary Rocks: Conglomerate, Sandstone and Shale, Chemical Sedimentary Rocks: Limestone, Dolomite and Evaporites, Organic Sedimentary Rocks: Coal and Chert).
- Metamorphic Rocks (e.g. Foliated Metamorphic Rocks: Slate, Schist and Gneiss, Non-foliated Metamorphic Rocks: Marble, Quartzite and Anthracite).
- Mineral resources, mining impacts, and sustainable resource management.
- Geological processes and their influence on environmental changes.
Quick Study Guide
Earth’s crust is composed of rocks, which are aggregates of minerals. Their structural behaviour and lifecycle are driven by chemical composition, thermodynamic cooling, and tectonic pressures.
- Mineral Properties and Classification: Minerals are inorganic solids with ordered atomic structures and definite chemical compositions. Silicates (e.g., quartz, feldspar) dominate the crust. Identification relies on physical properties like hardness (Mohs scale) and cleavage, which is the physical splitting of a mineral along structural planes of atomic weakness.
- Igneous Crystallisation and Bowen’s Series: Igneous rocks form as molten rock cools. Intrusive rocks (e.g., granite) cool slowly deep underground, growing coarse crystals; extrusive rocks (e.g., basalt) cool rapidly at the surface, forming fine-grained textures. Bowen’s Reaction Series dictates that mafic minerals (olivine, pyroxene) crystallise first at high temperatures, while felsic minerals (quartz) crystallise last at lower temperatures.
- Sedimentary Lithification: Sedimentary rocks result from the weathering, transport, and deposition of mineral grains. Unconsolidated sediments undergo lithification via compaction (driven by overlying geostatic pressure) and cementation (where mineral fluids precipitate in pore spaces to glue grains together), uniquely preserving stratification and fossils.
- Metamorphism and Foliation: Metamorphic rocks undergo solid-state structural and chemical changes due to intense heat, pressure, and chemically active fluids. Directional tectonic stress forces platy minerals to align perpendicularly, creating a layered texture called foliation. The structural orientation of these deformed strata is quantified by strike (horizontal intersection line) and dip (angle of downward inclination).
- The Rock Cycle and Isostasy: The rock cycle describes the continuous transformation of lithospheric material between igneous, sedimentary, and metamorphic states. On a macro-scale, isostasy governs the gravitational equilibrium between Earth’s buoyant crust and the denser mantle, adjusting crustal elevation as mass is redistributed by erosion or tectonic mountain building.
Test Your Knowledge
This quiz contains 25 concept-based MCQs on “Environmental Geosciences-Concept of Minerals & Rocks“. Each question has a single correct/most appropriate answer.
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1. What controls the formation of landforms, including mountains, valleys, and plateaus?
a) Biological processes
b) Climatic processes
c) Tectonic processes
d) Chemical weathering
2. In Bowen’s reaction series, which mineral is the last to crystallise from a cooling magma?
a) Muscovite
b) Olivine
c) Quartz
d) Biotite
3. The concept of a pluton is associated with the emplacement of:
a) Sedimentary rocks
b) Intrusive igneous rocks
c) Metamorphic rocks
d) Volcanic rocks
4. The cementation process is important in which type of rock formation?
a) Sedimentary
b) Igneous
c) Foliated
d) Metamorphic
5. The process of compaction in sedimentary rock formation is primarily driven by:
a) Chemical reactions
b) Biological activity
c) Pressure from overlying sediments
d) High temperatures
6. Which mineral is a common indicator of ultramafic rocks?
a) Pyroxene
b) Amphibole
c) Feldspar
d) Quartz
7. The concept of strike and dip is used to describe the orientation of:
a) Sedimentary rocks
b) Igneous rocks
c) Metamorphic rocks
d) Rock layers or beds
8. What classification system categorises elements based on their geochemical behaviour and abundance in Earth’s crust?
a) Mohs scale
b) Bowen’s reaction series
c) Goldschmidt classification
d) Dana classification
9. The major mineral component of granite is:
a) Biotite
b) Muscovite
c) Feldspar
d) Quartz
10. The concept of metamorphism is related to the:
a) Alteration of existing rocks
b) Cooling of molten magma
c) Breakdown of minerals into ions
d) Formation of sedimentary rocks
11. The rock cycle involves the continuous transformation of rocks between the three main types: igneous, sedimentary, and:
a) Clastic
b) Crystalline
c) Metamorphic
d) Foliated
12. The Mohs scale is used to measure the:
a) Hardness of minerals
b) Density of minerals
c) Melting point of minerals
d) Cleavage of minerals
13. Which type of rock is formed from the cooling and solidification of molten magma beneath the Earth’s surface?
a) Metamorphic rock
b) Extrusive igneous rock
c) Sedimentary rock
d) Intrusive igneous rock
14. The mineral halite is commonly associated with which type of sedimentary rock?
a) Sandstone
b) Shale
c) Limestone
d) Conglomerate
15. The concept of isostasy is primarily associated with the equilibrium between the Earth’s:
a) Atmosphere and lithosphere
b) Core and mantle
c) Hydrosphere and lithosphere
d) Crust and mantle
16. Which mineral group includes minerals like quartz, feldspar, and mica?
a) Silicates
b) Sulfides
c) Carbonates
d) Oxides
17. __________ is an essential component of both mica and clay minerals.
a) Quartz
b) Muscovite
c) Biotite
d) Feldspar
18. Which of the following is NOT a characteristic of sedimentary rocks?
a) Foliation
b) Stratification
c) Ripple marks
d) Fossils
19. Which type of rock results from the recrystallisation of existing rocks due to high temperature and pressure?
a) Metamorphic rock
b) Igneous rock
c) All types of rocks
d) Sedimentary rock
20. In the context of minerals, the term cleavage refers to:
a) The tendency of a mineral to break along certain planes
b) The alignment of mineral grains
c) The colour of a mineral in powdered form
d) The way a mineral reflects light
21. Which type of rock is formed through the solidification of molten magma?
a) Metamorphic
b) Sedimentary
c) Igneous
d) Foliated
22. The concept of mass wasting refers to:
a) Slow downslope movement of Earth’s material
b) Chemical breakdown of minerals
c) Formation of sedimentary rocks
d) Movement of rocks due to glacial activity
23. Which of the following is a common characteristic of foliated metamorphic rocks?
a) Volcanic origin
b) High quartz content
c) Layering or banding
d) Random crystal orientation
24. What is the primary criterion for classifying minerals into different groups?
a) Colour
b) Specific gravity
c) Cleavage
d) Hardness
25. The mineral pyrite, also known as fool’s gold, is often associated with which type of rock?
a) Shale
b) Slate
c) Sandstone
d) Limestone
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Next: Geophysical Fields
References
- Edward A. Keller (2022). Introduction to Environmental Geology, Pearson, 5th Edition.
- Sharma, P. D. (2017). Environmental Biology and Toxicology, Rastogi Publications, 3rd Edition.
- De, Anil Kumar and De, Arnab Kumar (2024). Environmental Chemistry, New Age International, 11th Edition.
- Odum, Eugene P., and Barrett, Gary W. (2004). Fundamentals of Ecology, Thomson Brooks/Cole, 5th edition.
- Singh, J.S., Gupta, S.R., Singh, S.P. & Singh, R. (2026). Ecology, Environmental Science and Conservation, S Chand Publishing, 2nd Edition.
- Erach Bharucha (2017). Environmental Studies, Universities Press, 4th Edition.
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