Question 1 - Past Year Questions - 5 Marks - Chapter 5 Class 10 Geography - Minerals and Energy Resources - Geography

‘Minerals occur in various forms.’’ Support this statement with examples.

Answer :

Explanation :

Answer to be written in the exam 

1. IN IGNEOUS AND METAMORPHIC ROCKS :

• Minerals may occur in cracks, crevices, faults or joints. Smaller occurrences are called veins and larger ones are called lodes.
• In most cases, they are formed when minerals in liquid/ molten and gaseous forms are forced upward through cavities towards the earth’s surface. 
• Major metallic minerals like tin, copper, zinc, lead, etc. are obtained from veins and lodes.

2. IN SEDIMENTARY ROCKS  

• They have been formed as a result of deposition, accumulation and concentration in horizontal strata. 
• Coal and some forms of iron ore have been concentrated as a result of long periods under great heat and pressure.
• Sedimentary minerals also include : Gypsum, potash salt, sodium salt. They are formed as a result of evaporation especially in arid regions.
  
  

3. DECOMPOSITION Of SURFACE ROCKS : 

• Another mode of formation involves DECOMPOSITION OF SURFACE ROCKS or removal of soluble constituents , leaving a residual mass of weathered material containing ores. 
• Bauxite is formed this way.
• a number of minerals occur in beds or layers.
  
  

4. ALLUVIAL DEPOSITS : 

• Certain minerals occur as alluvial deposits in sands of valley floors and base of hills.
• These deposits are called ‘ placer deposits’ and contain minerals, which are not corroded (destroyed) by water.
• Gold, silver, tin and platinum are most important among such minerals.
  
  

5. OCEAN WATERS :

•  contain vast quantities of minerals, but most of these are too widely diffused to be of economic significance.
• Common salt, magnesium, bromine are largely derived from ocean waters.
• The ocean beds are rich in manganese nodules.

(all 5 subheadings to be explained ; 1x5)