Ilimin kasan Indiya

Farantin a cikin ɓawon burodi na duniya, bisa ga ka'idar tectonics

ilimin ƙasa na Indiya ya bambanta. Yankuna daban-daban na Yankin Indiya suna dauke da duwatsu na lokutan geologic daban-daban, tun daga Zamanin Eoarchean. Wasu daga cikin duwatsu sun lalace sosai kuma sun canzawa. Sauran ajiya sun haɗa da alluvium da aka ajiye kwanan nan wanda har yanzu bai shiga cikin diagenesis ba. Ana samun ma'adanai iri-iri a cikin subcontinent a cikin adadi mai yawa. Ko da tarihin burbushin Indiya yana da ban sha'awa wanda aka haɗa da stromatolites, invertebrates, vertebrates da burbushin shuke-shuke. Za'a iya rarraba yankin ƙasar Indiya zuwa cikin Deccan Traps, Gondwana da Vindhyan.

Deccan Traps ya rufe kusan dukkanin Maharashtra, wani ɓangare na Gujarat, Karnataka, Madhya Pradesh da Andhra Pradesh a gefe. A lokacin tafiyarsa zuwa arewa bayan ya rabu da sauran Gondwana, Indian Plate ya wuce wani wuri mai zafi, Réunion hotspot, wanda ya haifar da narkewa mai yawa a ƙarƙashin Indian Craton. Rugujewar ta fashe a saman craton a cikin babban ambaliyar ruwa, wanda ya haifar da Deccan Traps. An kuma yi tunanin cewa hotspot na Reunion ya haifar da rabuwa da Madagascar da Indiya.

Gondwana da Vindhyan sun hada da sassan su Madhya Pradesh, Chhattisgarh, Odisha, Bihar, Jharkhand, West Bengal, Andhra Pradesh. Rashin Gondwana ya samar da jerin duwatsu na musamman da aka ajiye a lokacin Permo-Carboniferous. Kogin Damodar da Sone da tuddai na Rajmahal a gabashin Indiya suna dauke da rikodin duwatsun Gondwana.

Binciken Geological na Indiya ya buga Jerin Tarihin Geological na Kasa a Indiya.

Rashin ruwa

Craton Na Indiya ya kasance wani ɓangare na babban nahiyar Pangaea . A wannan lokacin, abin da ke yanzu kudu maso yammacin Indiya an haɗa shi da Madagascar da kudancin Afirka, kuma abin da ke gabashin gabashin yanzu an haɗa shi ne da Ostiraliya. A lokacin Jurassic game da 160 Ma (ICS 2004), rifting ya sa Pangaea ya rabu zuwa manyan nahiyoyi biyu, wato Gondwana (zuwa kudu) da Laurasia (zuwa arewa). Craton na Indiya ya kasance a haɗe da Gondwana, har sai babban nahiyar ta fara rarraba game da farkon Cretaceous, kimanin shekaru miliyan 125 da suka gabata (ICS 2004). Bayan haka, farantin Indiya ya juya zuwa arewa zuwa Farantin Eurasia, a saurin da ya fi sauri a kowane farantin. Gabaɗaya an yi imanin cewa Farantin Indiya ya rabu da Madagascar kimanin shekaru Miliyan 90 da suka gabata (ICS 2004), duk da haka wasu shaidun tarihin rayuwa da na ƙasa sun nuna cewa an riƙe haɗin tsakanin Madagascar da Afirka a lokacin da Farantin Indiya suka yi karo da Farantin Eurasian kimanin shekaru Miliya 50 da suka gabata. Wannan orogeny, wanda ke ci gaba a yau, yana da alaƙa da rufe Tekun Tethys. Rufe wannan teku wanda ya haifar da Alps a Turai, da kuma yankin Caucasus a yammacin Asiya, ya haifar da Dutsen Himalaya da Dutsen Tibet a Kudancin Asiya. Abubuwan da ke faruwa a yanzu suna haifar da wasu sassan nahiyar Asiya don lalacewa zuwa yamma da gabas a kowane bangare na orogen. A lokaci guda tare da wannan haɗari, Farantin Indiya ya haɗu da Farantin Australiya da ke kusa, ya samar da sabon farantin mafi girma, Farantin Indo-Australia.

Juyin Halitta

Saboda yaduwar nahiyar, Indiya Plate ya rabu da Madagascar kuma ya yi karo da Eurasian Plate wanda ya haifar da kafa Himalayas.

Mataki na farko na juyin halitta ya kasance alama ce ta sanyaya da karfafawa na saman farfajiyar ƙasa a cikin Archaean Era (kafin shekaru biliyan 2.5) wanda aka wakilta ta hanyar fallasa gneisses da granites musamman a kan Peninsula. Wadannan sune ainihin Craton na Indiya. Yankin Aravalli shine ragowar farkon Proterozoic orogen da ake kira Aravali-Delhi Orogen wanda ya shiga tsoffin sassan biyu da suka hada da Craton na Indiya. Ya kai kimanin kilomita 500 (311 daga iyakar arewa zuwa tsaunuka masu nisa da tsaunuka na dutse zuwa Haryana, yana ƙare kusa da Delhi.

Ƙananan ƙwayoyin cuta, lalacewa (ƙuƙwalwa da lalacewa) da kuma metamorphism na gaba na Dutsen Aravalli suna wakiltar babban matakin orogenesis. Rushewar duwatsu, da kuma ci gaba da lalacewar turɓaya na ƙungiyar Dharwarian (Bijawars) suna nuna mataki na biyu. Ayyukan dutsen wuta da intrusions, waɗanda ke da alaƙa da wannan mataki na biyu an rubuta su a cikin abun da ke cikin waɗannan turɓaya.

Tun da farko zuwa Late Proterozoic (shekaru biliyan 2.5 zuwa 0.54), an ajiye ajiyar calcareous da arenaceous, wanda ya dace da tsarin yanayi mai laushi da tsaka-tsaki, an ajiye su a cikin Cuddapah da Vindhyan. Wadannan kwandon da ke kan iyaka ko kwance a cikin ginshiki na crystalline, an ɗaga su a lokacin Cambrian (500 Ma (ICS 2004)). Rashin ruwa gabaɗaya ba a canza shi ba kuma a wurare da yawa sun adana asalin su na asali. Vindhyans sun kunshi ƙananan Supergroup wanda aka ajiye a wani lokaci tsakanin ~ 1800-1600 Ma. Ƙananan duwatsun Vindhyan sun ɗan lalace (sun karkata) kuma jerin Upper Vindhyan suna kwance ba tare da bin ka'ida ba a kan Lower Vindhyan. Shekarar Upper Vindhyan (Kaimur, Rewa da Bhander) sedimentation yana da rikici. Dutsen Kaimur ya shiga cikin 1073 Ma Majhgawan kimberlite (Gregory et al., 2006) sabili da haka sun fi 1073 Ma. Rewa ya ƙunshi tarin lu'u-lu'u da ke nuna cewa an kafa su ne bayan Kaimur. Kungiyar Bhander ta mamaye Rewa. Meert da Pandit (2015) sun tattauna shaidar kai tsaye game da shekarun Upper Vindhyan waɗanda suka lura da kamanceceniya a cikin hanyoyin paleomagnetic daga 1073 Ma Majhgawan kimberlite, 1.1 Ga Mahoba dyke da kuma turɓaya na Bhander da Rewa Groups. Bugu da kari, binciken zircon da yawa sun kasa ware duk wani zamani da ya fi ~ 1000 Ma daga duwatsun Upper Vindhyan. Wani da'awar kwanan nan na burbushin Ediacaran "Dickinsonia" wanda ke cikin Upper Bhander (Retallack et al., 2021) ya buƙaci shekarun Ediacaran ga wannan rukuni; duk da haka, Meert et al. (2023) sun nuna cewa an kuskuren burbushin sabili da haka har yanzu ana muhawara da shekarun Upper Vindhyan.

Ana samun duwatsun Paleozoic na farko a cikin Himalayas kuma sun ƙunshi abubuwan da aka samo daga kudu da aka rushe daga craton crystalline kuma an ajiye su a kan dandalin Indiya.

A cikin Late Paleozoic, Permo-Carboniferous glaciations ya bar manyan ajiyar glacio-fluvial a fadin tsakiyar Indiya, a cikin sabbin basins da aka kirkira ta hanyar sag / normal faulting. Wadannan tillites da kuma abubuwan da aka samo daga glacially ana kiransu jerin Gondwanas. Dutsen da ya haifar da laifin ruwa na Permian (270 Ma (ICS 2004)).

Marigayi Paleozoic ya yi daidai da lalacewa da raguwar Gondwana supercontinent. Ga wannan motsi, ana iya danganta hauhawar turɓaya ta Vindhyan da kuma zubar da turɓaya na arewacin a cikin Tekun Himalayan.

A lokacin Jurassic, yayin da Pangea ya fara rarraba, manyan grabens sun kafa a tsakiyar Indiya cike da Upper Jurassic da Lower Cretaceous sandstones da conglomerates.

A ƙarshen Cretaceous Indiya ta rabu da Ostiraliya da Afirka kuma tana motsawa zuwa arewa zuwa Asiya. A wannan lokacin, kafin fashewar Deccan, hauhawa a kudancin Indiya ya haifar da raguwa a cikin Tekun Indiya da ke kusa. Bayyana waɗannan duwatsu suna faruwa a kudancin Indiya a Pondicherry da Tamil Nadu.

A ƙarshen Mesozoic daya daga cikin manyan fashewar dutse a tarihin duniya ya faru, Deccan lava yana gudana. Ya rufe fiye da kilomita 500,000 (193,051 sq , waɗannan suna nuna hutu na ƙarshe daga Gondwana.

A farkon Tertiary, matakin farko na orogeny na Himalayan, matakin Karakoram ya faru. Himalayan orogeny ya ci gaba har zuwa yau.

Babbar Indiya

Babbar Indiya ko Babban Basin Indiya yana nufin Farantin Indiya tare da tsawo na arewa wanda ko dai ya rushe a ƙarƙashin Eurasia ko kuma ya matsa kan (ko ya ja) tsoffin tsaunukan dutsen wuta na Eurasia da ke arewacin arewa. A sakamakon haka, ɓawon burodi na wannan yankin da ke bakin teku ya ragu a ƙarƙashin matsin lamba kuma ya yi kauri don zama abin da ke yau da Tibetan Plateau. An yi amfani da kalmar kafin ka'idar tectonic, amma kalmar ta ga karuwar amfani tun daga shekarun 1970s.

Indian Plate da Eurasian Plate sun haɗu har zuwa 3,600 kilometres (2,200 mi) (2,200 ± 35 kilometres (22 mi) km (22 . An rubuta taƙaitaccen ɓawon burodi na sama daga rikodin ilimin ƙasa na Asiya da Himalaya har zuwa kusan kilomita 2,350 kilometres (1,460 mi) (1,460 mi) ƙasa. Yawancin yankin da ya ɓace an tura shi a ƙarƙashin Asiya don samar da tsaunukan Tibet.

Manyan rukuni na dutse

Taswirar rarrabuwar lokaci na Indiya

1891 Taswirar yanayin ƙasa ta Indiya

Precambrian super-eon

Wani yanki mai yawa na Indiya, Garkuwar Indiya, ya ƙunshi Archean gneisses da schists waɗanda sune tsofaffin duwatsu da aka samu a Indiya. An rarraba duwatsun Precambrian na Indiya zuwa tsarin biyu, wato Tsarin Dharwar da tsarin Archaean (gneiss da schists).

Tsarin Dharwar

Duwatsun tsarin Dharwar galibi suna da asali, kuma suna faruwa a cikin ƙananan layi da ke kwance a kan gneisses da aka samu a gundumar Bellary, Mysore da Aravalis na Rajputana. Wadannan duwatsu sun wadata da Manganese da ma'adinin ƙarfe wanda ke wakiltar muhimmiyar hanya ta waɗannan ƙarfe. Har ila yau, ana amfani da su sosai tare da zinariya musamman ma ma'adinan zinariya na Kolar da ke Kolar. A arewa da yammacin Indiya, tsarin Vaikrita, wanda ke faruwa a yankunan Hundar, Kumaon da Spiti, jerin Dailing a Sikkim da jerin Shillong a Assam an yi imanin cewa suna da shekaru iri ɗaya da tsarin Dharwar.

Ginin metamorphic ya ƙunshi gneisses waɗanda aka ƙara rarraba su cikin gneiss na Bengal, Bundelkhand gneiss da Nilgiri gneiss. Tsarin Nilgiri ya ƙunshi Charnockites daga dutse zuwa Gabbros.

Palaeozoic

Ƙananan Paleozoic

Ana samun duwatsu na farkon ɓangaren zamanin Cambrian a cikin Salt range a Punjab da yankin Spiti a tsakiyar Himalayas kuma sun ƙunshi jerin burbushin burbushin halittu. A cikin Salt range, stratigraphy ya fara ne da Salt Pseudomorph zone, wanda ke da kauri na 450 feet (137 m) kuma ya ƙunshi dolomites da sandstones. An rufe shi da sandstones na magnesia tare da kauri na 250 feet (76 m) , kama da dolomites na asali. Wadannan sandstones suna da burbushin halittu kaɗan. A kan sandstones shine Neobolus Shale, wanda ya ƙunshi duhu shales tare da kauri na 100 feet (30 m) . A ƙarshe akwai wani yanki wanda ya kunshi ja ko purple sandstones da ke da kauri na 250 feet (76 m) zuwa 400 feet (122 m) da ake kira Purple Sandstone. Wadannan ba su da burodi kuma suna nuna hasken rana da burrows na tsutsotsi waɗanda ke da alaƙa da yanayin iska. An san ajiyar a Spiti da tsarin Haimanta kuma sun ƙunshi slates, micaceous Quartzite da dolomitic limestones. Duwatsun Ordovician sun hada da flaggy shales, limestones, jan quartzites, quartzites da conglomerates. Siliceous limestones na Silurian sun rufe duwatsun Ordovician. Wadannan dutsen dutse suna rufe da fararen quartzite kuma wannan an san shi da Muth quartzite. Ana samun duwatsun Silurian waɗanda ke ƙunshe Dabbobi Silurian na musamman a cikin gundumar Vihi ta Kashmir.

Upper Paleozoic

Ana samun burbushin Devonian da murjani a cikin dutse mai launin toka a tsakiyar Himalayas da kuma cikin baƙar fata a yankin Chitral. Carboniferous ya ƙunshi jeri daban-daban guda biyu, na sama Carboniferous Po, da ƙananan Carboniferous Lipak. Ana samun burbushin brachiopods da wasu trilobites a cikin duwatsu masu yashi da yashi na jerin Lipak. Dutsen Syringothyris a Kashmir shima na Lipak ne. Jerin Po ya wuce jerin Lipak, kuma Fenestella shales an haɗa su a cikin jeri na quartzites da shales masu duhu. A wurare da yawa Carboniferous an lullube shi da launin toka na agglomeratic, wanda aka yi imani da cewa asalinsu ne na volcanic. Yawancin nau'ikan samfuran samfuran ana samun su a cikin dutsen farar ƙasa na Permo-Triassic, wanda ya haifar da ana kiran waɗannan duwatsun a matsayin "limestone samfurin". Wannan dutsen farar ƙasa na asalin ruwa ne kuma an kasu kashi uku daban-daban na lithostratigraphic raka'a dangane da tarihin samfuran: Late Permian Chideru, wanda ya ƙunshi ammonawa da yawa, Late - Middle Permian Virgal, da na tsakiyar Permian Amb unit.

Mesozoic

A cikin Triassic da Ceratite gadaje, mai suna bayan ammonite ceratite, sun ƙunshi limestones na fage, sandstones da kuma marls.  Jurassic ya ƙunshi raka'a daban-daban.  Dutsen farar ƙasa na Kioto, ya shimfiɗa daga ƙananan Jurassic na tsakiya tare da kauri 2,000 ƙafa (610 m) zuwa ƙafa 3,000 (914 m).  Jurassic na sama yana wakilta da baƙar fata Spiti, kuma ya tashi daga Karakoram zuwa Sikkim.  Duwatsun da ake kira Cretaceous sun mamaye wani yanki mai nisa a Indiya.  A Kudancin Indiya, an raba duwatsun da ke kwance zuwa matakai hudu;  da Niniyur, da Ariyalur, da Trichinopoly (wani gunduma a cikin Madras Shugabancin Madras, rufe a yau gundumomi na Tiruchirappalli, Karur, Ariyalur da Perambalur), da kuma Utatur matakai.  A cikin mataki na Utatur duwatsu suna karɓar nodules na phosphate, wanda ya zama muhimmin tushen phosphates a cikin ƙasa.  A cikin lardunan tsakiya, gadaje masu kyau na Lameta sun ƙunshi bayanan burbushin halittu waɗanda ke taimakawa wajen ƙididdige shekarun Tarkon Deccan.  An kafa wannan jerin duwatsun basaltic kusa da ƙarshen lokacin Cretaceous saboda ayyukan volcanic.  Waɗannan magudanan ruwa sun mamaye yanki mai faɗin murabba'in mil 200,000 (520,000 km2).  Waɗannan duwatsun tushe ne na dutsen gini mai inganci kuma suna ba da ƙoshin yumɓu mai ƙyalƙyali, musamman dacewa da noman auduga.

Cenozoic

Lokaci na uku

A cikin wannan lokacin da Himalayan orogeny ya fara, kuma volcanism hade da Deccan Traps ya ci gaba. Duwatsu na wannan zamanin suna da ma'adinan man fetur da kwal. Ana samun dutsen yashi na shekarun Eocene a Punjab, waɗanda ke zama ƙwanƙwasa alli tare da tsinken mai. Daga baya a arewacin duwatsun da aka samu a yankin Simla sun kasu kashi uku, jerin Sabathu da suka kunshi launin toka da jajaye, jerin Dagshai na yumbu mai haske da kuma jerin duwatsun kasauli. Zuwa gabas a Assam, ana samun dutsen farar ƙasa na Nummulitic a cikin tsaunukan Khasi. Ana danganta mai da waɗannan duwatsun zamanin Oligo-Miocene. A gefen tsaunin Himalayas Siwalik molasse yana kunshe da duwatsun yashi, conglomerates da shales masu kaurin ƙafa 16,000 (4,877 m) zuwa ƙafa 20,000 (6,096 m) kuma kama daga Eocene zuwa Pliocene. Waɗannan duwatsun sun shahara saboda wadatar dabbobin kashin baya ciki har da hominoids da yawa.

Lokacin Quaternary

Ruwan da aka samu a cikin filin Indo-Gangetic na wannan zamanin ne. An rushe shi daga Himalayas ta koguna da ruwan sama. Wadannan ajiyar alluvial sun kunshi yumɓu, laka, silt da dai sauransu kuma an raba su cikin tsofaffin alluvium da sabon alluvium. Tsohon alluvium ana kiransa Bhangar kuma yana cikin ƙasa sama da matakin ambaliyar koguna. Khaddar ko sabon alluvium an tsare shi a cikin tashoshin kogi da filayen ambaliyar su. Wannan yankin yana da wasu daga cikin ƙasa mafi kyau da aka samu a cikin ƙasar yayin da koguna ke ci gaba da shimfiɗa sabon laka a kowace shekara.

Girgizar ƙasa

Yankin Indiya yana da tarihin girgizar ƙasa mai lalacewa. Girgizar kasa ta Assam ta 1950 ta yi rajistar girman 8.6; tana ɗaya daga cikin girgizar ƙasa mafi ƙarfi da aka taɓa yin rikodin. Irin wannan girgizar ƙasa a yankin da ke da yawan jama'a a yau zai kashe daruruwan dubban idan ba miliyoyin ba. Wannan shine dalilin da ya sa aka yi imanin cewa yankin Himalayan yana daya daga cikin wurare masu haɗari don gina manyan madatsun ruwa. Babban dalilin da ya sa girgizar kasa ta yi yawa da tsananin girgizar ƙasa ita ce farantin Indiya yana motsawa zuwa Asiya a kusan 47 mm / shekara. Kididdigar ƙasa ta Indiya ta nuna cewa kusan kashi 54% na ƙasar tana da haɗari ga girgizar ƙasa. Wani rahoto na Bankin Duniya da Majalisar Dinkin Duniya ya nuna kimantawa cewa kimanin mazauna birni miliyan 200 a Indiya za su fuskanci guguwa da girgizar ƙasa nan da shekara ta 2050. Hukumar Kula da Bala'o'i ta Kasa ta ce kashi 60% na ƙasar Indiya tana fuskantar girgizar ƙasa kuma kashi 8% na iya fuskantar haɗarin guguwa.