Editing Geography of India (section)

== Geology ==
{{Main|Geology of India}}

[[File:Detrital rocks of Tirumala Hills Ghatroad Tirupati.JPG|thumb|[[Eparchaean Unconformity]] of Detrital rocks of Tirumala Hills, [[Eastern Ghats]]]]
India's geological features are classified based on their era of formation.<ref name="manorama6" /> The [[Precambrian]] formations of Cudappah and Vindhyan systems are spread out over the eastern and southern states. A small part of this period is spread over western and central India.<ref name="manorama6" /> The [[Paleozoic]] formations from the Cambrian, Ordovician, Silurian and Devonian system are found in the Western Himalaya region in Kashmir and Himachal Pradesh.<ref name="manorama6" /> The [[Mesozoic]] [[Deccan Traps]] formation is seen over most of the northern Deccan; they are believed to be the result of [[subaerial|sub-aerial]] volcanic activity.<ref name="manorama6" /> The Trap soil is black in colour and conducive to agriculture. The Carboniferous system, Permian System and Triassic systems are seen in the western Himalayas. The Jurassic system is seen in the western Himalayas and Rajasthan.
[[Image:India-geology-map.png|thumb|Geological regions of India]]
[[Tertiary]] imprints are seen in parts of Manipur, Nagaland, Arunachal Pradesh and along the Himalayan belt. The Cretaceous system is seen in central India in the Vindhyas and part of the Indo-Gangetic plains.<ref name="manorama6" /> The Gondwana system is seen in the Narmada River area in the Vindhyas and Satpuras. The Eocene system is seen in the western Himalayas and Assam. Oligocene formations are seen in Kutch and Assam.<ref name="manorama6" /> The [[Pleistocene]] system is found over central India. The Andaman and Nicobar Island are thought to have been formed in this era by volcanoes.<ref name="manorama6">{{cite book | title = Manorama Yearbook 2006 ''(India – Geology)'' |pages =521}}</ref> The Himalayas were formed by the convergence and deformation of the Indo-Australian and Eurasian Plates. Their continued convergence raises the height of the Himalayas by one&nbsp;centimetre each year.

Soils in India can be classified into eight categories: alluvial, black, red, laterite, forest, arid and desert, saline and alkaline and peaty and organic soils.<ref name="IA">{{cite web|title=India Agronet – Soil Management|url=http://www.indiaagronet.com/indiaagronet/soil_management/Soil_mgmt.htm|publisher=Indiagronet.com|access-date=18 July 2007|archive-date=25 June 2007|archive-url=https://web.archive.org/web/20070625143107/http://www.indiaagronet.com/indiaagronet/soil_management/Soil_mgmt.htm|url-status=live}}</ref><ref name="fao">{{cite web|title=Fertilizer use by crop in India|work=U.S. Food and Agriculture Organization|url=http://www.fao.org/docrep/009/a0257e/A0257E02.htm|access-date=2 August 2007|archive-date=5 November 2007|archive-url=https://web.archive.org/web/20071105080712/http://www.fao.org/docrep/009/a0257e/A0257E02.htm|url-status=live}}</ref> Alluvial soil constitute the largest soil group in India, constituting 80% of the total land surface.<ref name="fao" /> It is derived from the deposition of silt carried by rivers and are found in the Great Northern plains from Punjab to the Assam valley.<ref name="fao" /> Alluvial soil are generally fertile but they lack nitrogen and tend to be phosphoric.<ref name="fao" /> [[National Disaster Management Authority (India)|National Disaster Management Authority]] says that 60% of Indian landmass is prone to [[earthquake]]s and 8% susceptible to cyclone risks.

Black soil are well developed in the Deccan lava region of Maharashtra, Gujarat, and Madhya Pradesh.<ref name="krishi">{{cite web|title=Krishi World website |url=http://www.krishiworld.com/html/soils10.html |publisher=Krishiworld.com |access-date=18 July 2007 |url-status=dead |archive-url=https://web.archive.org/web/20070609175008/http://www.krishiworld.com/html/soils10.html |archive-date= 9 June 2007}}</ref> These contain high percentage of clay and are moisture retentive.<ref name="fao" /> Red soils are found in Tamil Nadu, Karnataka plateau, Andhra plateau, Chota Nagpur plateau and the Aravallis.<ref name="krishi" /> These are deficient in nitrogen, phosphorus and humus.<ref name="fao" /><ref name="krishi" /> Laterite soils are formed in tropical regions with heavy rainfall. Heavy rainfall results in leaching out all soluble material of top layer of soil. These are generally found in Western ghats, Eastern ghats and hilly areas of northeastern states that receive heavy rainfall. Forest soils occur on the slopes of mountains and hills in Himalayas, Western Ghats and Eastern Ghats. These generally consist of large amounts of dead leaves and other organic matter called [[humus]].

===Cratons===
[[File:India topo big.jpg|thumb|Topography of India]]
{{anchor | Craton | Cratons of India | Indian Craton | Indian Shield}}
[[File:Malani Igneous Suite Jodhpur near Mehrangarh Fort.jpg|thumb| Malani Igneous Suite, largest in India and third largest igneous suite in the world, at Jodhpur near [[Mehrangarh Fort]].]]

[[Craton]]s are a specific kind of [[continental crust]] made up of a top layer called [[Platform (geology)|platform]] and an older layer called [[Basement (geology)|basement]]. A [[Shield (geology)|shield]] is the part of a craton where basement rock crops out of the ground, and it is relatively the older and more stable section, unaffected by [[plate tectonics]].<ref name="cratonm2">[https://www.slideshare.net/pramodgpramod/cratons-of-india Cratons of India] {{Webarchive|url=https://web.archive.org/web/20210912162139/https://www.slideshare.net/pramodgpramod/cratons-of-india|date=12 September 2021}}.</ref><ref name="cratonm1">[http://mem.lyellcollection.org/content/43/1/151 Cratons of India] {{Webarchive|url=https://web.archive.org/web/20190116100217/http://mem.lyellcollection.org/content/43/1/151|date=16 January 2019}}, lyellcollection.org.</ref>

The Indian Craton can be divided into five major cratons as such:
* Aravalli Craton (Marwar-Mewar Craton or Western Indian Craton): Covers [[Rajasthan]] as well as [[Tosham Hill range|western]] and [[South Haryana|southern]] [[Haryana]]. It comprises Mewar Craton in the east and Marwar Craton in the west. It is limited by the ''Great Boundary Fault'' in the east, sandy Thar Desert in the [[Thar desert]] in the west, Indo-ganetic alluvium in the north, [[Son River|Son]]-[[Narmada River|Narmada]]-[[Tapti River|Tapti]] in the south. It mainly has [[quartzite]], [[marble]], [[pelite]], [[greywacke]] and extinct volcanos exposed in [[Aravalli-Delhi Orogen]]. [[Jodhpur Group – Malani Igneous Suite Contact|Malani Igneous Suite]] is the largest in India and third largest [[Igneous rock|igneous]] suite in the world.
* Bundelkand Craton, covers 26,00&nbsp;km<sup>2</sup> in the [[Bundelkhand]] region of [[Uttar Pradesh]] and [[Madhya Pradesh]] and forms the basis of the Malwa Plateau. It is limited by the [[Aravalli Range|Aravalli]] in the west, Narmada river and Satpura range in the south, and Indo-Gantetic alluvium in the north. It is similar to the Aravali Craton, which used to be a single craton before being divided into two with the evolution of [[Hindoli]] and [[Mahakoshal]] belts at the margins of two cratons.
* [[Dharwar craton|Dharwar Craton]] (Karnataka Craton), 3.4 - 2.6 Ga, [[granite]]-[[Greenstone belt|greenstone]] terrain covers the state of [[Karnataka]] and parts of eastern and southern [[Maharashtra]] state, and forms the basis of the southern end of the Deccan Plateau. In 1886 it was divided into two tectonic blocks, namely Eastern Dharwar Craton (EDC) and Western Dharwar Craton (WDC).
* Singhbhum Craton, 4,000&nbsp;km<sup>2</sup> area which primarily covers [[Jharkhand]] as well as parts of [[Odisha]], northern [[Andhra Pradesh]], northern [[Telangana]] and eastern Maharashtra. It is limited by the Chhota Nagpur Plateau to the north, Eastern Ghats to the southeast, Bastar Craton to southwest and alluvium plain to the east.
* Bastar Craton (Bastar-Bhandara Craton), primarily covers [[Chhattisgarh]] and forms the basis of the Chhota Nagpur Plateau. It is a remnant of 3.4-3.0 Ga old [[Tonalite-trondhjemite-granodiorite|TTG]] [[gneiss]]es of five types. It is subdivided into Kotri-Dongagarh [[Orogeny|Orogen]] and the Rest of Bastar Craton. It is limited by three [[rift]]s, [[Godavari]] rift in southwest, [[Narmada]] rift in northwest and [[Mahanadi]] rift in northeast.