A wasu sassan duniyar tamu, zamu iya ganin wani irin yanayin yanayin ƙasa wanda yake cike da raƙuman ruwa da iska ta ɗauke. Wannan ake kira tafki mara nauyi. Don irin wannan yanayin samaniya ya samu, wataƙila, dole ne dubunnan shekaru su shude, inda guguwar turɓaya mai ci gaba ta ajiye wannan kayan.
A cikin wannan labarin, zamu bayyana muku mahimmancin tankin Loess da manyan halayensa.
Loess tafki da samuwar shi
Kamar yadda muka ambata a baya, yana daukar tsawan shekaru dubbai kafin iska ta samar da wadannan kudaden kadan da kadan. A wasu sassan duniya muna samun irin wannan horon kuma abin mamaki ne. Lokacin da rafin Loess ya bi ta rafi ko yanke don yin hanyoyi, yawanci yana riƙe da tsari tsaye. Wannan shine inda ba ku da matakan da ake gani kamar yadda yake.
Rarraba ajiyar Loess yana nuna cewa akwai manyan tushe da yawa na abubuwan tsirrai don wannan samuwar: na farko shine rarar hamada da ke tarawa da ƙarfin iska, na biyun kuma shi ne magudanan ruwan kankara. Wadannan hanyoyin horo guda biyu suna da alhakin Loess.
Theididdigar Loess mafi kauri da faɗi a duniya sune waɗanda muke iya gani a yamma da arewacin China. Waɗannan kuɗaɗen an ƙirƙira su ne ta hanyar jigilar iska daga ƙauyuka masu yawa na hamada na Asiya ta Tsakiya. Wasu daga cikin wadannan tsarukan sun kasance tsayin mita 30 kuma abu ne gama gari a gani. A cikin kauri, an kafa matsakaita a girman mita 100. Wannan laka yana tarawa kuma, misali, shine ya samar da launi zuwa rafin rawaya.
A gefe guda kuma, a cikin Amurka, ajiyar Loess sun fi muhimmanci a yankuna da yawa inda ake samun jigilar abubuwa a nesa. Misali, a cikin Dakota ta Kudu, Nebraska, Missouri da Illinois, yankuna ne inda zamu sami waɗannan gine-ginen. Hakanan ana iya ganin su a wasu filayen Columbia a arewa maso yammacin Pacific.
Tushen
Akwai daidaito tsakanin rarraba Loess tare da manyan yankuna na noma na Midwest da jihar Washington. Wannan ba daidaituwa bane kwata-kwata, amma yana da alaƙa da shi. Saboda kasa da aka samo daga wannan laka shine ana ajiye shi ta hanyar iska suna daga cikin mafiya inganci a duniya. Godiya ga tarin kayan, abubuwan gina jiki suma suna tarawa. Ya zama yanki mai dausayi sosai don noma.
Ba kamar abin da ke faruwa tare da ajiyar ƙasar Sin ba, waɗanda suka samo asali daga hamada, na Amurka da Turai samfuran kai tsaye ne na kankara. Daskarewa da narkewa na shekaru dubbai da yawa, suna haifar da tsari da adana abubuwa masu ƙayatarwa wanda ke ƙaruwa da yawan albarkatun ƙasa. A gefe guda kuma, waɗancan kuɗaɗen da aka samar da kwandon yashi ba su da kirki kwata-kwata. Suna haifar da tsari ne kawai tare da kyawawan wurare amma tare da ƙaramar haihuwa.
Asalin ɗakunan ajiya na Loess a Amurka da Turai sune tarkace masu kankara. Lokacin da kankara suka fara ja da baya saboda karuwar yanayin zafi, an toshe kwaruruka da yawa tare da daskararrun da ake ajiyewa ta ruwan narkewar kankara. A wannan yanayin, wakilin da ke jigilar abubuwan da ke cikin ba iska ba ne, amma ruwan narkewa ne. Iska ma ta yi aikinta, tun da ta hura zuwa wani yamma zuwa yamma, ta share ta kuma ɗauki da yawa daga cikin abubuwan da ke cikin filayen ambaliyar.
An kwashe jigin daga mafi kyau zuwa mafi girma. A cikin motsi, sun fadi kamar bargo a kan gangaren gabas na kwari. Ana iya tabbatar da asalin waɗannan tsarin ta gaskiyar cewa Loess adibas an fi bayyana su a cikin yankuna masu hawa inda ake samun manyan wuraren magudanan ruwa. Misali, an fi jin daɗi sosai a yankunan kogin Mississippi da Illinois kuma sun zama sirara yayin da tazara daga kwarin ke ci gaba da ƙaruwa.
Wata hujja ta wannan asalin shine hatsi masu kusurwa waɗanda za'a iya ganinsu a yanayi kuma hakan yana haifar da Loess. Ana iya ganin cewa daidai suke da waɗanda zamu iya samu a cikin ƙasan dutsen da aka samar da shi a niƙa na kankara.
Halaye na zahiri na tankin Loess
Wadannan kudaden sun zama 10% na dukkan kasa a duniya. Kalmar Loess tana nufin cewa ƙasa ta zama sako-sako kuma ta ƙunshi 50% silt da kuma wani kaso 50% na yumbu. Yayin da nisa daga asalin fitarwa ya karu, yawan hatsin da aka ajiye ya ragu kuma, sabili da haka, adadin ya ragu a kauri da tsawo.
Tushen na iya zama na gari ko na nesa. Saboda haka akwai nau'ikan Loess. Misali, lemun tsami ko carbonate wasu daga cikin halayen halayen da muke samu a cikin Loess. Nau'in da adadin carbonate da muke da su ya dogara da tsarin samuwar kafin da bayan sanyawar dutsen da ruwan sama wanda ya daidaita su.
Kasancewa kwance, benaye basu da ƙarfi sosai. Sun fi ƙarfi lokacin da suka bushe, amma har yanzu suna iya narkewa cikin sauƙi lokacin da aka jiƙa a ruwa. Soilasa na iya ƙunsar tsakanin 10 zuwa 15% na ruwa tare da porosity wanda ya bambanta tsakanin 34 da 60%. Waɗannan masu canjin suna canzawa dangane da yawan yumbu ko yashi da muke da su.
Kamar yadda muka ambata a baya, ana buƙatar adana su sosai don noma mai zurfi. Wannan yana sa ayyukan noman su zama masu sauki kuma yana tabbatar da isasshen yanayi don ƙasa tana da kaddarorin kuma asalin shukokin suna girma cikin yanayi mai kyau.
Ina fatan cewa tare da wannan bayanin zaku iya ƙarin koyo game da ajiyar Loess.