TAMIL NADU GEOLOGY AND MINING for TNPSC Exams
TAMIL NADU 2016, Part:4 - GEOLOGY AND MINING PROFILE
Mineral form the basic resources for several important industries and contribute substantially to the Gross State Domestic Product and Industrial Growth. Mineral are considered to be the backbone for the economic growth and deemed to be the wealth of the country. The development activities of the State and its economic prosperity are reflected by the availability of mineral wealth and its prudent exploitation.
Tamil Nadu is endowed with several industrial minerals like Lignite, Limestone, Garnet Sand, Silica Sand, Quartz and Feldspar, Graphite, Oil and Natural Gas, Magnesite, Iron Ore etc., and also common use minor minerals deposits including world famous black granite and multi colour granite deposits which enabled in setting up of Cement, Refractory, Glass, Ceramic and Granite polishing industries in the state.
MINERAL RESOURCES OF THE STATE
- The rich and varied mineral resources of the State have contributed handsomely towards the development and industrialization of the State.
- It is one of the leading States in the reserves of the minerals viz., Lignite, Garnet, Magnesite, Quartz, Feldspar, Clay, Limestone, Bauxite, Graphite and Granite.
- Tamil Nadu represents an important high grade Metamorphic Terrain of Global Importance.CLICK here get Geologic map of Tamil Nadu
- Over the year, the Granite Industry has grown from strength to strength contributing more than 35% of the country's exports.
- During 1996-97, Tamil Nadu exported granite products valued at Rs.4.0 billion and other minerals; Rs.5.10 billion.
- The current annual production of cement is over 5 million tonnes. Lignite is being used to generate power. Graphite is yet another mineral offering opportunities for down-stream industries.
THE REGION-WISE RESOURCES
Geologically divided resources as the Central Region, Northern Region and Southern Region
The Central Region
- The Central Region divides the North and South by a comparatively smaller East-West zone which is about 50 Km wide.
- The central region is marked by two prominent tectonic zones viz., East-West trending Moyar-Bhavani-Attur (MBA) on the North and Palghat-Noyyil-Cauvery (PNC) in the South.
- Largely made up of reworked gneiss's carrying enclaves of older schists, amphibolites, Fuchsite quartzite, Banded magnetite quartzite, calc-granulites with limestone, and layered Anorthosite complex (Bhavani layered complex and Sittampundi complex).
- Dolerites are comparatively less in this zone and are exposed with many younger granites of Proterozoic age.
The Northern RegionThe Southern Region
- Northern region is occupied by the Amphibolite facies terrain, which is the Southern extension of Dharwar craton.
- There is a transitional zone extending from Mangalore to Chennai that separates the amphibolite terrain from the predominantly Charnockite terrain of Chennai-Chengalpattu, Javadi, Shevaroy Hills, Chitteri and Kalrayan massifs.
- The major metabasic occurrence in the North zone is the amphibolite in Vepanapalli-Maharajagadai area, which is the southern extension of the Kolar (Gold-bearing) schist belt, form the Kolar group of rocks.
- There are many Banded Magnetite Quartzites (BMQ) which run to few hundred metres in length noticed throughout the Northern Tamil Nadu of which the major ones are the Kavuthimalai, Vediyappanmalai, Kanjamalai and Thirthamalai.
- The intrusion of swarms of dolerite dykes are concentrated in Sholingar - Gudiyattam - Krishnagiri belt.
- Important occurrences of Alkaline complexes (Comprising Saturated Syenites and Sarbonatites closely associated with Ultra-Basic Rocks
- Occurs to the south of the Palghat-Cauvery tectonic zone.
- On the west of this zone charnokites form the massifs of the Western Ghats and the Eastern part is predominantly of Gneisses.
- This region differs from the Northern and Central regions by the predominance of Meta-Sedimentry Rocks such as Quartzites, Sillimanite Quartzites, Calc-Granulites, Garnet and Cordierite bearing Meta-Pelites.
- This zone is totally devoid of Dolerite Dykes and banded magnetite Quartzites.
- In the Northern part of this region Calc-Silicates and crystalline limestone occur as thick sequences for a few tens of metres thickness.
- Extensive limestone deposits are found from Palayam to Kiranur, Rajapalayam-Alangulam belt east of Varshanad hills and Talaiyuthu near Tirunelveli.
- At the southern extremity of peninsular India and to south of the Achankoil shear zone consist of Garnet-biotite-graphite Gneisses and Garnetiferous Charnockite and Khondalites (Garnet-Sillimanite-biotite-graphite), Cordierite Gneiss.
MINERALS WEALTH OF TAMIL NADU
(in Million Tonnes)
(Sources: Dept. of Geology & Mining, Govt. of Tamil Nadu)