The Chotanagpur Plateau
The Chotanagpur Plateau
The Chotanagpur plateau is the physical foundation of Jharkhand. It is an ancient block of hard Precambrian rock, worn down over long ages, tilted and faulted, and it is the reason the state holds India's richest concentration of minerals.
Rock base — ancient Precambrian crystalline rock | Coal — in Gondwana rocks of the valleys
What kind of landform it is
- A plateau, not a mountain range — a raised, worn-down block of old rock
- Part of the wider Peninsular Plateau of India
- Built mainly on Precambrian granite, gneiss and schist
- Long erosion has produced a stepped surface at several levels
- The state's rivers cut deep valleys into this surface
- The plateau tilts broadly toward the east and south-east
Why it holds so many minerals
- Ancient crystalline rocks carry iron, copper, bauxite, mica and uranium
- The Gondwana rocks laid down in rift valleys carry coal
- The Damodar valley is the classic Gondwana coal basin of India
- Laterite capping on the Pat surfaces gives bauxite
- The Singhbhum belt is one of India's oldest copper and iron zones
- This mineral wealth explains the state's industry, its migration and its politics
Surface features it produces
| Feature | Why it forms | Example |
|---|---|---|
| Waterfalls | Rivers drop from one plateau level to the next | Hundru, Dassam, Jonha |
| Steep scarps | Faulted plateau edges | Edge of the Pat region |
| Trough valleys | Rift-like depressions | Damodar valley |
| Residual hills | Harder rock left standing after erosion | Parasnath, Dalma |
| Laterite caps | Long weathering in a monsoon climate | Pat surfaces near Netarhat |
The name and the region
- Chotanagpur covers the plateau tract of present Jharkhand and adjoining areas
- One explanation links the name to Chutia, an early Nagvanshi capital, and Nagpur
- The Chotanagpur division was an administrative unit under British rule
- The CNT Act, 1908 takes its name from this region
- Today the tract is divided into the North and South Chotanagpur divisions
Human consequences of the plateau
- Thin soil and hard rock make irrigation difficult and farming rain-dependent
- Water runs off quickly, so the state has surplus rainfall but water scarcity
- Mining and industry cluster where the mineral belts lie, leaving other districts behind
- Forest cover survives on the slopes that could not be ploughed
- The plateau's isolation is why tribal societies here retained their institutions so long
Rock groups of the state
| Rock group | What it gives | Where |
|---|---|---|
| Precambrian crystalline | Iron, copper, mica, bauxite base | Singhbhum, Ranchi, Koderma belts |
| Gondwana | Coal | Damodar valley and North Karanpura side |
| Deccan trap type basalt | Basaltic hills | Rajmahal hills |
| Laterite | Bauxite | Pat surfaces of Latehar and Gumla |
छोटानागपुर पठार प्रायद्वीपीय पठार का हिस्सा है और प्री-कैंब्रियन कठोर चट्टानों से बना है। इसी संरचना के कारण यहां खनिजों की इतनी विविधता है।
Memory hook — Ek line me poora pathar — Purani chattan = khanij, Gondwana ghati = koyla, Pat ki laterite = bauxite. Teen chattan, teen khanij.
Yahan confuse hote hain — Coal aur baaki khanij alag chattanon me milte hain.
✗ Coal is found in the Precambrian crystalline rocks | ✓ Coal is in Gondwana rocks of the valleys; iron and copper are in the older crystalline rocks
✗ Chotanagpur ek parvat shrinkhala hai | ✓ Chotanagpur ek pathar hai, parvat shrinkhala nahi
Exam pointer — JPSC me plateau ki chattan aur khanij ka rishta Prelims aur Mains dono me aata hai — 'Gondwana rocks kis khanij se jude hain' type. JSSC aur JKCE me seedha — Chotanagpur kis prakar ka bhu-roop hai. Is topic ko chapter 9 ke khanij ke saath milakar padho, dono ek hi kahani hain.
Ek nazar me
- A plateau of the Indian Peninsular block
- Base rock — Precambrian granite, gneiss and schist
- Coal lies in Gondwana rocks of the valleys
- Damodar valley — classic Gondwana coal basin
- Bauxite comes from laterite caps on the Pat surfaces
- Singhbhum — ancient copper and iron belt
- Waterfalls form at plateau steps — Hundru, Dassam, Jonha
- Residual hills — Parasnath, Dalma
- Thin soil makes farming rain-dependent
- The CNT Act is named after this region