Why Chhotanagpur Plateau is rich in minerals?
Answers
During the original cooling and solidification of earth as the temperature decreased different substances started freezing which included minerals. With this also continued the sinking of heavier minerals - sort of sorting. These constructs that had frozen minerals and have not been altered since are this rich in metalliferous minerals and are called shields or also basement rocks. These form Dharwar series, named according to Indian geological timescale.
Next came Cuddapah series on which transgressional effectiveness of seas added minerals like limestone, dolomite, etc.
Also relevant here is Gondwana series when trees felling under rift valleys, getting trapped and then getting pressurised by overlying strata led to formation of coals.
Chhota Nagpur Plateau has rocks of all these series in its geological structure and hence is rich in mineral resources.