Karnataka (the land of black soils) Plateau (11° 36′-18°26’N and 74° 35′-78°40’E) covers about 1, 83,340 sq. km of area in Karnataka state and parts of Cannanore and Kozhikode districts of Kerala. Geologically the region is very complex where rocks from the Archaean to the Recent are found (Archaeans occupying 75% of the total area).
Archaean rocks include granites, granodiorites, gneissic granites and banded or composite gneisses (Krishnan, 1960, p. 109). Dharwar system formed of phyllite schists and slates in the districts of Dharwar, Bellary, Shimoga and Chitradurga are highly metaliferous containing iron, manganese, copper, lead and gold (Kolar field).
The Cuddapah system is found in the form of Kaladgi and Kurnool series. The northern part of the region is covered by augite basalt of the Deccan Trap (150- 1300 m).
The region has an average elevation between 600-900 m. Mulangiri (1923 m) is the highest peak (Baba Budan Hills) followed by Kudremukh (1892 m). It is highly dissected region widi general trends of hills from north to south. The region has three distinct physiographic units : (i) Malnad, (ii) North- em Upland, and (iii) Southern Upland.
The Malnad (hill country) extending about 320 km in length is traversed by the Western Ghats. The Northern Upland, occypying about 45% of die region’s area, is a landscape of monotonous plateau covered with rich black cotton soil and treeless fields. Its average elevation lies between 300 m and 600 m characterised with broad flat bottomed valleys.
The Southern Upland is relatively higher (600-900 m) and more rugged. It consists of a series of rolling plateaus culminating into highly irregular and disjointed granitic hdls between Tumkur and Kolar. The main ridge lies between the Kaveri and the Tungabhadra. Melukote in Mandya district is a sheltered valley, while Nandi Hills is a summer resort.