The Deccan Plateau is a large plateau in peninsular India, covering much of the southern and central parts of the country. It is one of the oldest and most stable landmasses globally, characterized by its unique geological structure and diverse relief features.

Geological Structure: The Deccan Plateau is primarily composed of Deccan Traps, vast sheets of flood basalts that erupted during the late Cretaceous to early Paleocene epochs (60-68 million years ago). These volcanic eruptions created a layered structure of basaltic lava flows.

• Basaltic Rocks: Dominant rock type, dark, fine-grained, rich in iron and magnesium, highly resistant to erosion.
• Underlying Formations: Beneath the Deccan Traps are older Archaean gneisses and granites, Proterozoic sedimentary rocks, and some Gondwana sediments, exposed along the margins and in river valleys.
• Faulting and Folding: Experienced some faulting and minor folding, contributing to rift valleys (Narmada, Tapti) and block mountains.

Relief Features: The Deccan Plateau is an undulating upland with varying elevations, generally sloping from west to east, reflected in the eastward flow of most major peninsular rivers.

1. Western Ghats (Sahyadri):

   • Form the western edge, rising abruptly from the Konkan coastal plain.
   • Continuous chain of mountains, acting as a major physiographic barrier and watershed.
   • Steep escarpments on the west, gentler eastward slope. Average elevation 1,000-1,300 meters.
   • Origin of major eastward-flowing rivers (Godavari, Krishna, Kaveri).

2. Eastern Ghats:

   • Form the eastern edge, parallel to the Bay of Bengal coast.
   • Discontinuous, highly eroded, and dissected by rivers. Composed of older metamorphic rocks.
   • Lower in elevation (600-900 meters) compared to Western Ghats.

3. Central Highlands/Plateau Interior:

   • Vast area between the Ghats, characterized by rolling plains, isolated hills, and river basins.
   • Maharashtra Plateau: Covered by Deccan Traps, with 'trap topography' (flat-topped hills, step-like slopes).
   • Karnataka Plateau: Higher elevations in the west (Malnad) and rolling plains in the east (Maidan).
   • Telangana Plateau: Semi-arid, undulating topography, composed of granite and gneissic rocks.
   • Chota Nagpur Plateau: Northeastern part, rich in minerals, dissected plateaus and residual hills.
   • Bundelkhand and Baghelkhand Plateaus: Northern extension, granite and sandstone formations.

4. River Valleys: Major rivers like Godavari, Krishna, and Kaveri have carved extensive fertile alluvial plains. Narmada and Tapti flow westward through rift valleys.

5. Residual Hills and Inselbergs: Isolated hills and remnants of ancient mountain ranges (e.g., Nallamala Hills) throughout the plateau.

The Deccan Plateau's structure and relief features profoundly influence India's climate, drainage, agriculture, and human settlement patterns.