Ambaliyar ruwa Basalt

.Asalin ambaliya (ko plateau basalt) shine sakamakon wani katon dutse mai aman wuta ko jerin fashewar da ke rufe manyan shimfidar kasa ko benen teku tare da lafazin basalt.  Yawancin basalt ambaliya an danganta su da farkon wani wuri mai zafi da ya isa saman duniya ta hanyar tulun alkyabba.  Lardunan basalt ambaliya irin su Deccan Traps na Indiya ana kiran su tarkuna, bayan kalmar Sweden trappa (ma'anar "matakin bene"), saboda yanayin yanayin matattarar matakala na yawancin shimfidar wurare masu alaƙa.

Michael R. Rampino da Richard Stothers (1988) sun ambaci abubuwan ambaliyar ruwa guda goma sha ɗaya da suka faru a cikin shekaru miliyan 250 da suka gabata, suna haifar da manyan larduna masu zafi, tsaunuka masu laushi, da tsaunuka. Koyaya, an san ƙarin kamar babban Ontong Java Plateau, da kuma Chilcotin Group, kodayake ana iya danganta ƙarshen da Columbia River Basalt Group.

An haɗa manyan larduna masu cin wuta zuwa abubuwan da suka faru guda biyar,  kuma ana iya danganta su da tasirin bolide. 

## Bayyanawa

Rashin ambaliyar ruwa shine mafi girma daga dukkan duwatsun igneous masu tsananin gaske,  wanda ke samar da manyan ajiya na dutsen basaltic   wanda aka samu a duk tarihin ilimin ƙasa. Su ne wani nau'i mai ban sha'awa na dutsen wuta,  wanda aka ware daga duk sauran nau'ikan dutsen wuta ta hanyar manyan tarin dutsen da ya fashe a cikin gajeren lokaci. Lardin ambaliyar basalt guda ɗaya na iya ƙunsar daruruwan dubban cubic kilomita na basalt da ya fashe a ƙasa da shekaru miliyan, tare da abubuwan da suka faru kowannensu yana fashewa da daruruwan cubic kilomita nke basalt. Wannan dutsen basalt mai ruwa sosai na iya yaduwa a gefe don daruruwan kilomita daga asalinsa,  wanda ke rufe yankuna na dubban murabba'in kilomita. Girgizar fashewa da ke biyowa suna samar da tarin kusan kwance, suna fashewa cikin sauri a kan manyan yankuna, suna ambaliya a saman duniya tare da laka a kan sikelin yanki.

Wadannan tarin ambaliyar ruwa sun samar da manyan larduna masu zafi. Wadannan suna da siffofi na tsaunuka, don haka ana bayyana basalts na ambaliyar ruwa a matsayin basalts na tsaunukan. Canyons da aka yanke a cikin ambaliyar ruwa ta hanyar rushewa suna nuna gangaren da ke kama da matakala, tare da ƙananan sassan kwararru da ke samar da dutse da kuma saman ɓangaren kwararru ko yadudduka masu haɗuwa da ke samarwa. Wadannan an san su a cikin Yaren mutanen Holland a matsayin *tarko* ko a cikin Yammacin Yaren mutanen Sweden a matsayin trappa, wanda ya zo cikin Turanci a matsayin trap rock, kalmar da aka yi amfani da ita musamman a masana'antar dutse.

Babban kauri na tarin basalt, sau da yawa fiye da mita 1,000 (3,000 ,  yawanci yana nuna adadi mai yawa na ƙananan ruwa, ya bambanta da kauri daga mita zuwa dubban mita, ko kuma da wuya zuwa mita 100 (330 . A wasu lokuta akwai ruwa mai yawa. Ruwa mafi zurfi a duniya na iya zama Greenstone na Keweenaw Peninsula na Michigan, Amurka, wanda ke da mita 600 (2,000  kauri. Wannan kwararar na iya kasancewa wani ɓangare na tafkin lava girman Lake Superior.

Rugujewar ambaliyar ruwa mai zurfi yana fallasa adadi mai yawa na dicks masu layi daya waɗanda ke ciyar da fashewar. Wasu dicks a Filin Kogin Columbia suna da tsawon kilomita 100 (60 . A wasu lokuta, rushewar ƙasa yana fallasa tsarin radial na dikes tare da diamita na dubban kilomita. Sills na iya kasancewa a ƙarƙashin ambaliyar ruwa, kamar Palisades Sill na New Jersey, Amurka. Rashin shiga takarda (dikes da sills) a ƙarƙashin basalts na ambaliyar ruwa yawanci diabase ne wanda ya dace da abin da ke cikin basalts na ruwa. A wasu lokuta, sa hannun sinadarai yana ba da damar haɗa dikes guda ɗaya tare da kwararar mutum.

### Ƙananan siffofi
Ambaliyar basalt yawanci yana nuna haɗin gwiwa, wanda aka kafa yayin da dutsen ya sanyaya kuma ya yi kwangila bayan ya ƙarfafa daga lava.  Dutsen ya karye zuwa ginshiƙai, yawanci tare da bangarori biyar zuwa shida, daidai da alkiblar zafin da ke fitowa daga dutsen.  Wannan gabaɗaya yana daidai da saman sama da ƙasa, amma ruwan sama da ke kutsawa cikin dutsen ba daidai ba zai iya haifar da "yatsu masu sanyi" na karkatattun ginshiƙai.  Saboda zafin zafi daga tushe na kwarara yana da hankali fiye da daga samansa na sama, ginshiƙan sun fi na yau da kullum kuma sun fi girma a kasa na uku na kwarara.  Mafi girman matsin lamba na hydrostatic, saboda nauyin dutsen da ke sama, kuma yana ba da gudummawar yin ƙananan ginshiƙai mafi girma.  Ta hanyar kwatanci tare da gine-ginen haikalin Girka, ana siffanta ƙananan ginshiƙai na yau da kullun a matsayin colonnade da ƙarin karaya na sama marasa tsari a matsayin ɓarke ​​na guda ɗaya.  ginshiƙan sun kasance sun fi girma a cikin kwararowar kauri, tare da ginshiƙan ƙaƙƙarfan kwararar Greenstone, da aka ambata a baya, suna kusa da mita 10 (30 ft) kauri..

Wani nau'in ƙananan sikelin da aka saba na ambaliya basalts shine vesicles-bututu.  Ambaliyar ruwan basalt lava tana yin sanyi sannu a hankali, ta yadda iskar gas da ke narkar da su ke samun lokacin fitowa daga mafita kamar kumfa (vesicles) da ke ta iyo zuwa saman magudanar ruwa.  Yawancin sauran kwararan ruwa suna da yawa kuma babu vesicles.  Duk da haka, mafi saurin sanyaya lava kusa da gindin magudanar yana samar da wani ɗan ƙaramin sanyi mai sanyi na dutsen gilashi, kuma dutsen da ya fi kristal da sauri kusa da gefen gilashin yana ƙunshe da vesicles da ke makale yayin da dutsen ke daɗa kyalkyali da sauri.  Waɗannan suna da siffa ta musamman da aka kwatanta da bututun taba na yumbu, musamman kamar yadda vesicle yawanci daga baya cike da calcite ko wasu ma'adanai masu launin haske waɗanda suka bambanta da basalt ɗin duhu..

Har yanzu ƙananan ma'auni, yanayin basalts na ambaliyar ruwa shine aphanitic, wanda ya ƙunshi ƙananan lu'ulu'u masu haɗuwa. Wadannan lu'ulu'u masu haɗuwa suna ba da tarko mai ƙarfi da tsayi. Ana saka lu'ulu'u na plagioclase a cikin ko a lullu'u a kusa da lu'ulu-lu'u na pyroxene kuma suna daidaitawa ba zato ba tsammani. Wannan yana nuna wuri mai sashi don haka lava ba ta gudana da sauri lokacin da ta fara kirista. Rashin ambaliyar ruwa kusan ba shi da manyan phenocrysts, manyan lu'ulu'u da ke cikin laka kafin ya fashe zuwa farfajiyar, wanda sau da yawa yana cikin wasu duwatsu masu tsananin gaske. Phenocrysts sun fi yawa a cikin dikes da ke ciyar da laka zuwa farfajiyar.

Basalts na ambaliyar ruwa galibi sune Toleiites na Quartz. Olivine tholeiite (dutse mai mahimmanci na tsakiyar teku ) yana faruwa ba sau da yawa, kuma akwai lokuta masu ban sha'awa na alkali basalts. Ba tare da la'akari da abun da ke ciki ba, kwararar tana da daidaituwa sosai kuma ba ta ƙunshe da xenoliths, raguwa na dutsen da ke kewaye da ita (dutse na ƙasa) waɗanda aka kwashe a cikin lava. Saboda lavas suna da ƙarancin iskar gas, dutsen pyroclastic yana da matukar wuya. Sai dai inda kwararar ta shiga tabkuna kuma ta zama dutsen matashin kai, kwararar tana da yawa (ba ta da alama). Lokaci-lokaci, ambaliyar ruwa tana da alaƙa da ƙananan Dacite ko rhyolite (mafi yawan dutsen dutse mai cike da silica), wanda ke samar da marigayi a ci gaban babban lardin igneous kuma yana nuna canji zuwa mafi tsakiya volcanism.

Basalts na ambaliyar ruwa suna nuna babban matsayi na daidaitattun sunadarai a duk lokacin geologic,  kasancewar galibi basalts masu arziki na ƙarfe. Babban ilmin sunadarai na su yayi kama da basalts na tsakiyar teku (MORBs), yayin da ilmin sunayensu, musamman na abubuwa masu ban sha'awa na duniya, yayi kama da na tsibirin basalt na teku. Yawanci suna da abun ciki na silica na kusan 52%. Lambar magnesium (mol% na magnesium daga cikin jimlar ƙarfe da abun ciki na magnesium) yana kusa da 55,  da 60 don MORB na al'ada. Abubuwan da ba a saba gani ba na duniya suna nuna alamu masu yawa da ke nuna cewa asalin (na farko) magma ya samo asali ne daga dutse na mantle na Duniya wanda kusan ba a cika shi ba; wato, dutse ne mai wadata da garnet kuma daga abin da aka cire ƙaramin magma a baya. Kimiyyar plagioclase da olivine a cikin ambaliyar ruwa ta nuna cewa magma ya ɗan gurɓata da dutse mai narkewa na ɓawon duniya, amma wasu ma'adanai masu zafi sun riga sun fito daga dutsen kafin ya kai farfajiya. A wasu kalmomi, ambaliyar basalt ta samo asali ne daga matsakaici. Koyaya, ƙananan adadin plagioclase ne kawai suka bayyana sun fito daga narkewar.

Kodayake ana ɗaukar su a matsayin ƙungiya mai kama da sunadarai, ambaliyar ruwa a wasu lokuta tana nuna bambancin sunadarai har ma da lardin guda. Misali, ana iya raba ambaliyar ruwa ta Parana Basin zuwa ƙananan phosphorus da titanium (LPT) da kuma babban phosphorum da titanium group (HPT). An danganta bambancin ga rashin daidaituwa a cikin mantle na sama,  amma ƙididdigar isotope na strontium yana nuna bambancin na iya tasowa daga LPT magma da aka gurɓata tare da adadi mai yawa na narkewa. 

Ka'idojin da aka samu na ambaliyar ruwa dole ne a bayyana yadda za'a iya samar da irin wannan magma mai yawa kuma ya fashe kamar lava a cikin irin wannan gajeren lokaci. Dole ne kuma su bayyana irin wannan abun da ke ciki da saitunan tectonic na ambaliyar basalts da suka fashe a duk lokacin geologic da kuma ikon ambaliyar ambaliyar ruwa basalt lava don tafiya irin wannan nisa daga fissures na fashewa kafin ya karfafa.

### Zamani na narkewa
A tremendous amount of heat is required for so much magma to be generated in so short a time. This is widely believed to have been supplied by a mantle plume impinging on the base of the Earth's lithosphere, its rigid outermost shell. The plume consists of unusually hot mantle rock of the asthenosphere, the ductile layer just below the lithosphere, that creeps upwards from deeper in the Earth's interior. The hot asthenosphere rifts the lithosphere above the plume, allowing magma produced by decompressional melting of the plume head to find pathways to the surface.

Rukunin dicks masu layi daya da aka fallasa ta hanyar zurfin rushewar ambaliyar ruwa sun nuna cewa an sami fadadawa mai yawa. Rashin ruwa na yammacin Scotland da Iceland sun nuna tsawo har zuwa 5%. Yawancin basalts na ambaliyar ruwa suna da alaƙa da kwarin rift, suna kan gefen farantin nahiyar, ko kuma sun faɗaɗa cikin Aulacogens (makamai da suka gaza na mahaɗar uku inda rifting na nahiyar ya fara.) Basalts na ambaliya a kan nahiyoyi galibi ana daidaita su da hotspot volcanism a cikin tafkunan teku. Rashin Paraná da Etendeka, wanda ke cikin Kudancin Amurka da Afirka a bangarorin da suka gabata na Tekun Atlantika, an kafa shi kusan shekaru miliyan 125 da suka gabata yayin da Kudancin Atlantic ya buɗe, yayin da saiti na biyu na ƙananan ambaliyar ruwa ya kafa kusa da iyakar Triassic-Jurassic a gabashin Arewacin Amurka yayin da Arewacin Atlantic ya bude. Koyaya, ambaliyar ruwa ta Arewacin Atlantic ba ta da alaƙa da duk wata alama mai zafi, amma da alama an rarraba su daidai tare da duk iyakar da ta bambanta.

Sau da yawa ana haɗa basalts na ambaliyar ruwa tare da turɓaya, yawanci jan gadaje. Sanyawa na turɓaya ya fara ne kafin ambaliyar ruwa ta farko ta fashewa, don haka raguwa da raguwar ɓawon burodi sune abubuwan da ke haifar da aikin ambaliyar basalt. Yankin yana ci gaba da raguwa yayin da basalt ya fashe, don haka ana samun tsofaffin gadaje a ƙasa da matakin teku. An samo sassan basalt a zurfi (masu haskakawa) ta hanyar haskakawa ta hanyar hasashen girgizar ƙasa tare da gefen nahiyar.

### Hawan sama
Abubuwan da ke tattare da ambaliya basalt na iya nuna hanyoyin da magma ke kaiwa saman.  Narke na asali da aka kafa a cikin rigar babba (narkewar farko) ba zai iya samun abun da ke tattare da ma'adini tholeiite ba, mafi yawanci kuma yawanci mafi ƙanƙanta da aka samo asali daga dutsen tsaunuka na ambaliya basalts, saboda quartz tholeiites suna da wadatar baƙin ƙarfe dangane da magnesium don sun samo asali cikin ma'auni tare da dutsen mantle na al'ada.  Narke na farko na iya samun nau'in basalt picrite, amma picrite basalt ba a sani ba a lardunan basalt ambaliya.  Wata yuwuwar ita ce narkewar daɗaɗɗen narke lokacin da ta isa kan iyakar alkyabbar, inda ba ta da ƙarfin da zai iya ratsa dutsen ƙanƙara.  Kamar yadda tholeiitic magma ke bambanta (canje-canje a cikin abun da ke ciki kamar yadda ma'adanai masu zafin jiki ke yin crystallize kuma suna fita daga magma) yawansa ya kai mafi ƙanƙanta a adadin magnesium kusan 60, kama da na basalts na ambaliya.  Wannan yana dawo da buoyancy kuma yana ba da izinin magma don kammala tafiyarsa zuwa saman, sannan kuma ya bayyana dalilin da yasa basalts ambaliya galibin ma'adini tholeiites ne.  Fiye da rabin magma na asali ya kasance a cikin ƙananan ɓawon burodi kamar yadda aka tattara a cikin tsarin dikes da sillls.

Yayin da magma ke tashi, raguwar matsin lamba yana rage ruwa, zafin jiki wanda magma ke cike da ruwa. Wannan mai yiwuwa ya bayyana rashin phenocrysts a cikin ambaliyar ruwa. Resorption (rugujewa a cikin *sakewa*) na cakuda mai ƙarfi olivine, augite, da plagioclase - ma'adanai masu zafi da za su iya zama a matsayin phenocrysts - na iya kuma fitar da abun da ke ciki kusa da quartz tholeiite kuma su taimaka wajen kiyaye tashi.

### Fitarwa
Once the magma reaches the surface, it flows rapidly across the landscape, literally flooding the local topography. This is possible in part because of the rapid rate of extrusion (over a cubic km per day per km of fissure length) and the relatively low viscosity of basaltic lava. However, the lateral extent of individual flood basalt flows is astonishing even for so fluid a lava in such quantities. It is likely that the lava spreads by a process of *inflation* in which the lava moves beneath a solid insulating crust, which keeps it hot and mobile. Studies of the Ginkgo flow of the Columbia River Plateau, which is  thick, show that the temperature of the lava dropped by just  over a distance of . This demonstrates that the lava must have been insulated by a surface crust and that the flow was laminar, reducing heat exchange with the upper crust and base of the flow. It has been estimated that the Ginkgo flow advanced 500&nbsp;km in six days (a rate of advance of about 3.5&nbsp;km per hour).

Yankin gefen ambaliyar ruwa na basalt yana da kusan daidai da cube na kauri na kwarara kusa da asalinsa. Don haka, kwararar da ta ninka sau biyu a asalinsa na iya tafiya kusan sau takwas har zuwa yanzu.

Ruwan basalt na ambaliyar ruwa galibi ruwa ne na pāhoehoe, tare da 'a'ā yana gudana da yawa.

Fashewar fashewa a lardunan ambaliyar ruwa yana da lokaci, kuma kowane fashewa yana da sa hannun sinadarai. Akwai wasu halaye don lava a cikin fashewa guda ɗaya don zama mafi wadataccen silica tare da lokaci, amma babu wani tsari mai daidaituwa a duk abubuwan da suka faru.

## Manyan larduna masu cin wuta
 

## Tasirin

### Tsarin ɓawon burodi
Extrusion na ambaliyar basalts, matsakaici a tsawon lokaci, ana iya kwatanta shi da yawan extrusion na lava a tsakiyar tsaunuka na teku kuma ya fi girma fiye da yawan extrusions ta hotspots. Koyaya, extrusion a tsakiyar tsaunuka na teku yana da daidaituwa, yayin da extrusion na ambaliyar ruwa yana da matukar damuwa. Ambaliyar ruwa ta haifar da sabon ɓawon burodi na nahiyar a cikin 0.1 zuwa 8  kilomita (0.02 zuwa 2   a kowace shekara, yayin da fashewar da ke samar da tsaunuka na teku ke samar da 2 zuwa 20 cubic kilomita (0,5 zuwa 5 cu mi) na ɓawon burogi a kowace shekara.

Yawancin sabon ɓawon burodi da aka kafa a lokacin ambaliyar basalt yana ɗaukar nau'in underplating, tare da sama da rabin asalin magma da ke fitowa yayin da yake tarawa a cikin sills a gindin ɓawon burodin.

An danganta fashewar ambaliyar ruwa da lalacewar jama'a. Misali, Deccan Traps, wanda ya fashe a iyakar Cretaceous-Paleogene, na iya ba da gudummawa ga halaka dinosaur da ba tsuntsaye ba. Hakazalika, yawan jama'a a iyakar Permian-Triassic, iyakar Jurassic_event" id="mwAeo" rel="mw:WikiLink" title="Triassic-Jurassic event">Triassic-Jurassic, kuma a cikin Toarcian Age na Jurassic ya dace da Shekaru manyan larduna masu cin wuta a Siberia, lardin Magmatic na Tsakiyar Atlantic, da Karoo-Ferrar basalt.

Ana iya ba da wasu ra'ayoyi game da tasirin ambaliyar ruwa ta hanyar kwatanta da manyan fashewar tarihi. Fashewar Lakagígar ta 1783 ita ce mafi girma a cikin tarihin tarihi, inda ta kashe kashi 75% na dabbobi da kashi ɗaya cikin huɗu na yawan mutanen Iceland. Koyaya, fashewar ta samar da kawai 14  kilomita (3.4   na lava,   wanda yake karami idan aka kwatanta da Roza Member na Columbia River Plateau, ya fashe a tsakiyar Miocene, wanda ya ƙunshi aƙalla 1,500 cubic kilomita (360 cu mi) ya lava.

During the eruption of the Siberian Traps, some  of magma penetrated the crust, covering an area of , equal to 62% of the area of the contiguous states of the United States. The hot magma contained vast quantities of carbon dioxide and sulfur oxides, and released additional carbon dioxide and methane from deep petroleum reservoirs and younger coal beds in the region. The released gases created over 6400 diatreme-like *pipes*, each typically over  in diameter. The pipes emitted up to 160 trillion tons of carbon dioxide and 46 trillion tons of methane. Coal ash from burning coal beds spread toxic chromium, arsenic, mercury, and lead across northern Canada. Evaporite beds heated by the magma released hydrochloric acid, methyl chloride, methyl bromide, which damaged the ozone layer and reduced ultraviolet shielding by as much as 85%. Over 5 trillion tons of sulfur dioxide was also released. The carbon dioxide produced extreme greenhouse conditions, with global average sea water temperatures peaking at , the highest ever seen in the geologic record. Temperatures did not drop to  for another 5.1 million years. Temperatures this high are lethal to most marine organisms, and land plants have difficulty continuing to photosynthesize at temperatures above . The Earth's equatorial zone became a dead zone.

Koyaya, ba duk manyan larduna masu cin wuta ba ne ke da alaƙa da abubuwan da suka faru. Halitta da tasirin ambaliyar ruwa sun dogara da dalilai da yawa, kamar tsarin nahiyar, latitude, girma, ƙimar, tsawon fashewa, salon da saiti (continental vs. oceanic), yanayi da ya riga ya kasance, da kuma juriya ga canji.

## Jerin ambaliyar ruwa
Wakilan ambaliyar ruwa na nahiyar da tsaunuka na teku, an shirya su ta hanyar tsari na lokaci, tare suna samar da jerin manyan larduna masu cin wuta: 

An bayyana Maria a kan Wata a matsayin basalts na ambaliyar ruwa  wanda ya ƙunshi basalt na picritic.  Abubuwan fashewa na mutum suna iya kama da girman ambaliyar ruwa na Duniya, amma an raba su da tsawo kuma ana iya samar da su ta hanyoyi daban-daban.