Peninsular India

 

Peninsular India: Peninsular India comprises of Indian craton which is of two types

(1)Indian Shield: Example- Folded mountains and massifs.

Rocks Age: Archean and Lower Proterozoic.

(2)Platform Cover: Example- Plateau mountains, Graben

Rocks Age: Middle and upper Proterozoic sequence in central part and Phanerozoic sequence in Coastal and outer regions of the craton.

 

Indian Shield:

It has four stages of tectonic evolution.

(!) The Older Greenstone Belt: Remnants of Primordial crust that comprises the oldest rocks exposed on the Indian Peninsula.

(!!) These rocks have been intruded by Peninsular Gneiss that is predominantly made up of granitic gneiss and migmatites.

The gneisses are also known as Fundamental Gneisses.

(!!!) Newer Greenstone belt: They formed the basement for the deposition of the oldest Volcano- Sedimentary sequence of the Indian shield.

These rocks were subjected to orogenic deformation and metamorphism.

(!!!!) Emplacement of large bodies of granitic plutons.

The largest granitic pluton, known as Closepet Granite; is exposed in N-S trending linear belt in the central part of south India.

 

 

Time Period:

ARCHEAN EON:

·        Early Archean Crust

·        Middle Archean Age: Iron Ore Orogeny in Singhbhum-keonjhar region.

·        Late Archean Age: Emplacement of the Peninsular Gneisses and High grade rocks in Eastern Ghats.

Example: Eastern Ghats, Dharwar Orogeny(South-late), Gave rise to the formation of Bundelkhand Gneiss.

These rocks are exposed in the form of Bundelkhand massif.

 

PROTEROZIC EON:

Early Proterozoic: Example- Aravalli Structural Trend

Aravalli region experienced two tectonic cycles-

Older one is deformed Aravalli supergroup rocks

Younger: Delhi Orogeny

Eastern ghats were also affected by yet another orogenic event.

Middle Proterozoic: Example- Satpura structural trend

Late Proterozoic: Example- Shillong plateau

 

PROTEROZOIC COVER(SEDIMENTARY PROCESSES)

Middle Proterozoic: Cuddapah Depression

Middle and upper Proterozoic: Vindhyan Syneclise

Equivalent rocks formation are exposed in Chattisgarh depression and Bastar depression.

 

PHANEROZOIC COVER

Lower Palaeozoic: Absent

Upper Palaeozoic and Mesozoic age: Deposition in three major rift valleys- Narmada-Son-Damodar Graben, Mahanadi Graben, Godavari Graben.

Palaeocene: Deccan traps(Terrestrial Volcanic Outbursts)

PEACE OUT

- Ichbinaasif