The correct Answer is A-2, B-1, C-4, D-3
Explanation
Minerals are naturally occurring substances with a definite chemical composition and a characteristic crystal structure. Their geological origin varies significantly based on the processes of formation, which include igneous, metamorphic, sedimentary, and residual weathering processes.
Statement-wise Analysis
- A. Coal - 2. Accumulation of fossilised vegetation
- Correct: Coal is a combustible black or brownish-black sedimentary rock formed from the accumulation and compaction of plant matter over millions of years under heat and pressure. This process is known as coalification, and it occurs in sedimentary basins.
- B. Mica - 1. Found in veins of metamorphic/igneous rocks
- Correct: Mica is a group of sheet silicate minerals that are commonly found in igneous and metamorphic rocks. It often occurs in pegmatite veins, which are coarse-grained igneous rocks, and in metamorphic rocks like schists and gneisses.
- C. Bauxite - 4. Residual mass of weathered material
- Correct: Bauxite is the primary ore of aluminum. It is a residual rock formed from the intense weathering of aluminum-rich rocks (like feldspar-rich igneous rocks) in tropical and subtropical climates. The weathering process leaches away soluble minerals, leaving behind insoluble aluminum hydroxides, which accumulate as bauxite.
- D. Copper - 3. Sulphide ore bodies in veins
- Correct: Copper is frequently found in nature as sulphide minerals (e.g., chalcopyrite, bornite). These sulphide ores often occur in veins and disseminated deposits associated with igneous and metamorphic processes, particularly in hydrothermal veins where hot, mineral-rich fluids deposit the metals.
Key Takeaway: The geological origin of minerals is diverse, with coal forming from organic matter, mica from igneous/metamorphic processes, bauxite from residual weathering, and copper typically from sulphide deposits in veins.