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Geological Map India |
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GEOLOGY OF INDIA
India has a diverse geology akin to that of her people,
climate and size. Its different regions contain rocks
of all types belonging to different periods of Geological
Time Scale. Some rocks are badly deformed and metamorphosed
while others are recently deposited alluvium that are
yet to undergo digenesis. Mineral deposits of great diversity
are found in the subcontinent in large quantity. Even
the fossil records are impressive in that they include
stromatolites, invertebrates, vertebrates and plant fossils.
India's geological features can be divided based on their
formation in different periods of the Geological Time
Scale. Accordingly, India's geographical land can be classified
into Deccan Trap, Gondwana and Vindhyan and into those
that originated in Pleistocene, Tertiary, and Pre-Cambrian
Period.
The Deccan Trap covers
almost all of Maharashtra, a part of Gujarat, Karnataka,
Madhya Pradesh and Andhra Pradesh marginally. Geologists
believe that the Deccan Trap was formed as result of
sub-aerial volcanic activity associated with continental
divergence in this part of the earth during the Mesozoic
era. The rocks found in this region are generally of
igneous type.
The Gondwana and Vindhyan
include within its fold parts of Madhya Pradesh, Chhattisgarh,
Orissa, Andhra Pradesh, Maharashtra, Jammu and Kashmir,
Punjab, Himachal Pradesh, Rajasthan and Uttaranchal.
The Gondwana Supergroup forms a unique sequence of fluviatile
rocks deposited in Permo-Carboniferous & Mesozoic
times. Damodar and Sone river valley and Rahmahal hills
in the eastern India are repositories of the Gondwana
rocks.
The vast plateau mountains
to the north of Narmada River in Madhya Pradesh and
the adjoining areas of Malwa Plateau and Gangetic Plains
form the Vindhyan cover. Here, the Deccan Trap and the
alluvium conceal the rocks. The lower Vindhyans (Semri
Group) are dominantly limestones, whereas the upper
parts of the succession are mostly sandstones.
Formations, which are
of recent or Pleistocene origin, are found over relatively
large area of India. Parts of the geographical area
of the states of Uttar Pradesh, Rajasthan, Punjab, Gujarat,
Madhya Pradesh, Tamil Nadu, Andhra Pradesh, Orissa,
Kerala, Karnataka, Maharashtra, Assam, Bihar and Haryana
come under this geological category.
The Tertiary period has
also left its imprints on the geological features of
Manipur, Nagaland, and parts of Arunachal Pradesh, Mizoram,
Assam, Tripura, Uttaranchal, Himachal Pradesh and Jammu
and Kashmir.
Geological formations of Pre-Cambrian period are predominantly
spread over large area of Andhra Pradesh, Orissa, Jharkhand,
Chhattisgarh, Tamil Nadu, Karnataka, Kerala, and marginally
over Gujarat, Rajasthan, Madhya Pradesh and Jammu and
Kashmir.
The following diagram
shows the different periods in the Geological Time Scale
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| Eon |
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Period |
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Unit: Ma (Mega annum) |
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| Era |
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Epoch |
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1 Ma = 106 years ago |
| PHANEROZOIC |
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Cenozoic |
65 - 0 Ma |
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Quaternary |
1.5 - 0.0 Ma
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Tertiary |
| Neogene |
26 - 1.5 Ma |
| Pliocene |
| Miocene |
| Palaeogene |
65 - 26 Ma |
| Oligocene |
| Eocene |
| Palaeocene |
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| Mesozoic |
230 - 65 Ma |
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Cretaceous |
136 - 65 Ma
| Late(Senonian) |
| Early(Neocomian) |
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Jurassic |
190 - 136 Ma
| Late(Maim) |
| Middle(Dogger) |
| Early(Lias) |
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Triassic |
230 - 190 Ma
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| Palaeozoic |
570 - 230 Ma |
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Permian |
280 - 230 Ma
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Carboniferous |
345 - 280 Ma
| Late(Pennsylvanian) |
| Early(Mississipian) |
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Devonian |
395 - 345 Ma
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Silurian |
430 - 395 Ma |
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Ordovician |
395 - 345 Ma
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Cambrian |
570 - 500 Ma
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| PRECAMBRIAN |
4600 - 570 Ma |
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Proterozoic |
2500 - 570 Ma |
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Upper |
1600 - 570 Ma |
| Middle |
2000 - 1600 Ma |
| Lower |
2500 - 2000 Ma |
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Archaean |
2500 - 570 Ma |
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Hadean |
4600 - 3800 Ma |
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