Layers na Duniya da Halayensu
Duniya ba ta da wani tsari na dutse iri ɗaya. A ƙarƙashin saman da muke zaune, Duniya ta ƙunshi layuka masu siffofi daban-daban na zahiri da sinadarai. Waɗannan bambance-bambancen suna tasiri kusan kowace irin yanayi ta ƙasa: girgizar ƙasa, fashewar aman wuta, samuwar duwatsu, kwararar ruwa ta nahiyar, har ma da filin maganadisu da ke kare rayuwa daga radiation mai cutarwa. Fahimtar layukan Duniya yana nufin fahimtar "injin" da ke tuƙa duniyar.
Gabaɗaya, ana iya bayyana layukan Duniya ta hanyoyi biyu: bisa ga abubuwan da suka ƙunshi sinadarai (ɓawon burodi, mantle, core) da kuma bisa ga halayen zahiri ko na inji (lithosphere, asthenosphere, mesosphere, external core, inner core). Waɗannan hanyoyi guda biyu suna ƙarawa juna ƙarfi.
1) Ƙashin Duniya: Sirara amma mai mahimmanci a waje
Bawon shine mafi girman saman Duniya, inda nahiyoyi da kuma ƙasan teku ke zama. Duk da cewa shine babban "matakin" rayuwa, ɓawon a zahiri siriri ne idan aka kwatanta da girman Duniya.
Babban halaye:
– Kauri: kimanin kilomita 5-10 ga ɓawon teku da kuma kilomita 30-70 ga ɓawon nahiya (ya yi kauri a ƙarƙashin manyan tsaunuka).
- Abun da aka haɗa:
- Bakin teku galibi dutse ne mai launin basaltic (mai wadataccen magnesium da baƙin ƙarfe).
– Ƙwayar nahiyar ta ƙunshi ƙarin duwatsu masu daraja (masu silica).
– Yawan: ɓawon teku ya fi kauri (mai yawa) fiye da ɓawon nahiya, don haka yana iya saukowa cikin sauƙi a ƙarƙashinsa.
– Zafin jiki: ƙasa idan aka kwatanta da yadudduka da ke ƙasa, amma yana ƙaruwa da zurfi.
An raba ɓawon zuwa faranti na tectonic waɗanda ke ci gaba da motsi. Wannan motsi na faranti yana haifar da girgizar ƙasa , yana buɗe sabbin tekuna, kuma yana samar da tsaunuka.
2) Riga: "Kitchen" Mai Sauƙi a Ƙarƙashin Ƙirgar
A ƙarƙashin ɓawon akwai mantle, mafi kauri a duniya, wanda ya kai mafi yawan girman duniyar. Sau da yawa ana ɗaukar mantle a matsayin teku na magma, amma a zahiri galibi yana da ƙarfi. Duk da haka, filastik ne—yana iya gudana a hankali a kan lokutan ilimin ƙasa.
Babban halaye:
– Kauri: kimanin kilomita 2.900, daga tushen ɓawon zuwa iyakar tsakiya.
– Abun da ke ciki: ya mamaye ma'adanai masu silicate masu wadataccen magnesium da ƙarfe (misali peridotite).
– Zafin jiki: yana farawa daga ~500°C a saman zuwa sama da 4.000°C kusa da iyakar tsakiya.
– Muhimmin tsari: mantle convection currents, waɗanda sune motsin kayan zafi da ke tashi da kuma nutsewar kayan sanyi. Wannan shine ɗayan manyan abubuwan da ke haifar da motsi. faranti na tectonic.
An raba mayafin zuwa babban mayafin da kuma ƙaramin mayafin. A wasu yankuna, narkewar wani ɓangare yana faruwa, yana haifar da mayafin. Wannan mayafin na iya tashi sama ya haifar da ayyukan aman wuta.
3) Ciki na Duniya: Tsakiyar Duniya da Tushen Filin Magnetic
Mafi girman matakin ciki na Duniya shine tsakiyar, wanda galibi ya ƙunshi ƙarfe da nickel. Tsakiyar tana taka muhimmiyar rawa domin ita ce tushen filin maganadisu na Duniya, wanda ke aiki a matsayin "garkuwa" daga iskar rana da ƙwayoyin da aka caji.
Babban halaye:
– Wuri: daga zurfin ~2.900 km zuwa tsakiyar Duniya a ~6.371 km.
– Abun da aka haɗa: ƙarfe (Fe) da nickel (Ni), tare da yuwuwar samun wasu abubuwa masu haske kaɗan.
– Rabawa: tsakiyar waje (ruwa) da kuma tsakiyar ciki (mai ƙarfi).
– Matsayi: motsin ruwa mai sarrafawa a cikin tsakiyar waje yana haifar da tasirin dynamo wanda ke samar da filin maganadisu na Duniya.
Ba tare da wani abu mai aiki a cikin zuciyar Duniya ba, da alama Duniya za ta fi fuskantar barazanar radiation kuma iskar rana za ta iya lalata yanayinta cikin sauƙi, kamar yadda ake tsammanin ta faru a duniyar Mars.
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Yanka-yanka bisa ga Kayan Aiki na Jiki (Injini)
Baya ga rarrabuwar ɓawon burodi-mantle-core, masana kimiyyar ƙasa galibi suna amfani da rarrabuwa bisa ga "yadda yadudduka ke aiki" dangane da matsin lamba da zafi.
4) Lithosphere: Harsashi mai tauri wanda aka karya zuwa faranti
Lithosphere ya haɗa da ɓawon burodi da kuma ɓangaren sama mai tauri. Wannan shine Layer ɗin da ke samar da faranti na tectonic.
Babban halaye:
– Halaye: masu tauri, masu karyewa, masu sauƙin fashewa—shi ya sa girgizar ƙasa ke faruwa sau da yawa a cikin lithosphere.
– Kauri: ya bambanta, kimanin kilomita 50-200, yana iya zama mai kauri a ƙarƙashin tsoffin nahiyoyi.
– Matsayi: motsawa a kan ƙarin filastik ɗin da ke ƙasa da shi (asthenosphere), yana haifar da hulɗar faranti kamar bambance-bambance, haɗuwa, da canji.
A iyakokin faranti daban-daban, lithosphere na iya shimfiɗawa da samar da tsaunukan tsakiyar teku. A iyakokin haɗuwa, lithosphere mai yawa na teku yana iya shiga cikin mantle, yana samar da ramukan teku da kuma tsaunukan aman wuta.
5) Tauraron Sama: Layin "Taushi" Wanda Ke Bada Damar Motsa Faranti
Tauraron sararin samaniya yana ƙarƙashin lithosphere, gami da ɓangaren da ya fi zafi da ruwa a saman mantle.
Babban halaye:
– Properties: filastik, yana iya yin lahani kuma yana gudana a hankali.
– Yanayi: sau da yawa yana fuskantar narkewar ɗan kaɗan a cikin ƙananan kashi, yana sa shi ya zama "mai rauni a zahiri".
– Matsayi: zama "saman da ke zamewa" wanda faranti na lithospheric ke zamewa a kai, ta yadda faranti na tectonics za su iya faruwa.
Tauraron taurari yana da mahimmanci don bayyana dalilin da yasa faranti zasu iya motsawa duk da cewa lithosphere yana da tauri da kauri.
6) Mesosphere (Ƙasa da Riga): Tauri amma tana gudana a hankali
Mesosphere sau da yawa yana nufin ƙananan mantle (ƙasa da sararin samaniya zuwa iyakar tsakiya). Duk da yawan zafin da yake da shi, babban matsin lamba yana sa shi ya yi ƙarfi.
Babban halaye:
– Halaye: sun fi tauri fiye da taurarin sararin samaniya, amma har yanzu suna iya gudana akan sikelin lokaci na miliyoyin shekaru.
– Matsayi: yana taimakawa wajen zagayawa tsakanin manyan mantle convection da ke motsa zafi daga cikin Duniya zuwa sama.
Haɗakar da ke cikin ƙananan mantle tare da saman mantle yana samar da tsarin jigilar zafi wanda ke shafar ayyukan ilimin ƙasa a saman.
7) Tsarin Waje: Karfe Mai Ruwa Yana Tuƙa Filin Magnetic
Jikin waje yana ƙarƙashin mantle kuma ruwa ne. Guduwar wannan ƙarfe mai ruwa yana da matuƙar muhimmanci.
Babban halaye:
– Zurfin: ~2.900–5.150 km.
– Halaye: ruwa saboda haɗuwar zafin jiki mai yawa da wasu yanayi na jiki.
– Babban aiki: samar da filin maganadisu ta hanyar motsin convection na ƙarfe mai sarrafa ruwa da kuma juyawar Duniya (geodynamo).
Canje-canje a cikin kwararar ruwa a cikin tsakiyar waje suma suna da alaƙa da bambance-bambancen ƙarfin filin maganadisu, har ma da juyawar sandar maganadisu akan lokacin ilimin ƙasa.
8) Ciki na Ciki: Ƙwallo Mai Ƙarfi Mai Matsi Mai Tsanani
A tsakiyar Duniya akwai wani ƙarfi a cikin zuciyarta. Duk da tsananin yanayin zafi, matsin lamba mai yawa yana sa ƙarfe da nickel su taurare.
Babban halaye:
– Zurfin: ~5.150–6.371 km (zuwa tsakiyar Duniya).
– Dabi'u: mai yawa, mai matsewa sosai.
– Zafin jiki: an kiyasta zai kai ~5.000–6.000°C.
– Matsayi: yana taimakawa wajen kiyaye yanayin aiki na tsakiya, kuma tsarin daskarewa a hankali na tsakiya na ciki zai iya sakin zafi da haske waɗanda ke ƙarfafa convection a cikin zuciyar waje.
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Ta Yaya Masana Kimiyya Suka San Yankunan Duniya?
Domin ba za mu iya haƙa ramin cikin zuciyar ba, iliminmu game da tsarin Duniya ya samo asali ne daga ilimin girgizar ƙasa. Raƙuman girgizar ƙasa suna tafiya ta hanyoyi daban-daban ta hanyar daskararru da ruwa. Raƙuman P na iya ratsawa ta cikin daskararru da ruwa, yayin da Raƙuman S ba za su iya ba. Tsarin karkacewa da "yankunan inuwa" na raƙuman girgizar ƙasa suna nuna cewa tsakiyar waje ruwa ne kuma tsakiyar ciki yana da ƙarfi. Bugu da ƙari, bayanai daga nauyi, filayen maganadisu, da gwaje-gwajen ma'adinai masu matsin lamba suna da amfani.
Penutup
Layukan duniya—ɓawon burodi, mantle, da kuma tsakiya—ba wai kawai rabe-raben tsari ba ne, amma tsarin aiki ne masu haɗin kai. Lithosphere mai tauri yana motsawa akan taurarin filastik masu yawa, yana ƙirƙirar tectonics na faranti waɗanda ke siffanta saman duniyar. Mantle ɗin yana aiki azaman injin convection wanda ke canja wurin zafi, yayin da ruwan ciki na waje yana samar da filin maganadisu wanda ke kare rayuwa. Ta hanyar fahimtar halayen kowane layi, za mu iya fahimtar dalilin da yasa Duniya take da ƙarfi, mai rayuwa, kuma tana canzawa akai-akai akan lokaci.
