Dune na ciki

Dune na ciki sune dunes na yashi na iska waɗanda ake samu a cikin ƙasa, nesa da yankunan bakin teku.

 Kafawa 
A Tsakiyar Turai, zuwa ƙarshen lokacin glacial na ƙarshe (kimanin shekaru 12,000 da suka gabata), ya kasance kusan digiri 10 ya fi sanyi fiye da yau. Saboda haka babu wani gandun daji amma kawai tsire-tsire masu tsayi a cikin nau'in tundra. Bugu da ƙari, a cikin yankunan da kankara ta rufe, tsire-tsire dole ne su sake kafa kansu yayin da kankara suka narke. A sakamakon haka, iskõki na iya busa kusan ba tare da wani cikas ba. Haske, ƙwayoyin ƙasa masu kyau, musamman na yashi da yashi an ɗauke su da iska, galibi ana jigilar su mil sannan a ajiye su a wani wuri. Har ila yau, iska tana da tasirin rarraba - ana jigilar silt da sauri fiye da yashi - kuma wannan ya haifar, a tsawon lokaci, a yankunan yashi da yashi da aka kafa, yayin da aka kai silt da yawa kuma aka sake sanya shi, alal misali, a gefen arewacin tsaunuka.

A cikin iska mai ƙarfi dunes suna da halin "tafiya". Yawancin dunes na cikin gida a halin yanzu an halicce su ne a wannan lokacin. Tare da ƙarshen lokacin glacial, motsi na dunes da sauri ya tsaya sakamakon sake dasa bishiyoyi.

Siffar dunes na ciki ya bambanta dangane da hanyar iska da ƙarfi. Yawancin su dunes ne marasa daidaituwa ko belin yashi mai canzawa. Amma kuma akwai abubuwan da suka faru da kyau sosai da kuma dunes masu tsawo.

Kusan dukkanin matakai na baya-bayan nan na ci gaban dunes na cikin gida suna shafar sa hannun mutum a kan shuke-shuke. Ta hanyar kwashe gandun daji da gangan ko ba da gangan ba, dunes sun sake zama masu motsi a wuraren da suka zama masu tsayawa.

Binciken ƙwayoyin gawayi a cikin dunes ta amfani da kwanan wata na radiocarbon ya tabbatar da cewa aikin mazauna a lokacin Neolithic ya sa dunes su sake zama masu motsi. Amma har ma a cikin Bronze da Iron Age akwai shaidar aikin dune da mutum ya haifar.

 Rarraba 

 Arewacin Amurka 
Yawancin dunes na iska suna cikin Arewacin Amurka, gami da dunes na eolian na tsire-tsire (tsayawa) na US Atlantic Coastal Plain, dunes na yankin Laurentian Great Lakes, dunes of the Central and Southern Great Plains, the Nebraska Sand Hills, White Sands (New Mexico), Great Sand Dunes (Colorado), dunes of Southern Colorado Plateau, da kuma filayen dune na Kudu maso Yammacin Deserts.

 Baja California

Yankin yashi na cikin gida na El Vizcaíno Desert, Baja California, Mexico, ya fito ne daga maɓuɓɓugar ruwa da ke kusa. Asalin yashi ana zaton ya samo asali ne daga granitoids, schists da kuma dutsen dutse da dutsen wuta. Duk da yake abun da ke ciki ya nuna cewa yashi na dune ya fito ne daga tsarin craton geochemistry yana nuna saitin gefen nahiyar mai aiki don asalin yashi.

 Kudancin Amurka 

 Pampas na Argentina

Manyan filayen burbushin burbushin halittu ko filayen paleo-dune sun kasance a Lardin La Pampa na Argentina. Wadannan dune sune alamun yanayin yanayi na baya yanka ya ba da izinin motsi na yashi. Dunes ba sa aiki kuma saboda tasirin ciyawa. Koyaya dunes sun lalace ta hanyar ciyawa da noma. Wani filin dune na musamman ya rufe bene na kwarin NE-SW mai tsawon kilomita 40 da faɗin kilomita 5. Ya ƙunshi manyan dunes na parabolic tare da ƙananan dunes da aka gina a saman.  

 Dajin Atacama

Kusa da Copiapó a kudancin hamadar Atacama akwai mafi girman dunes na Chile. Dangane da nazarin turɓaya an ba da shawarar cewa dunes sun samo asali ne daga turɓaya na kogi. Bayani na baya ya nuna cewa dunes sun samo asali ne daga yashi na bakin teku a cikin wuraren da aka ɗaga, to, raguwa zai haifar da wannan yashi ya yi ƙaura zuwa cikin ƙasa. A halin yanzu dunes suna aiki amma suna fama da yunwa.

 Babban Chaco

Dune-dune na ciki a cikin Gran Chaco na Bolivia da Paraguay sun fi mayar da hankali a tuddai na Andes. Yawancin waɗannan dunes ba sa aiki tare da wasu suna da shekaru dubu 33-36.

 Turai 

 Tsakiyar Turai

A cikin Tsakiyar Turai, sabili da haka, dunes na ciki sun cire Aelian dunes na bakin teku a Tekun Arewa da Tekun Baltic. Ba kamar 'yan uwan su na bakin teku ba, dunes na ciki sune tsarin yashi na eolian (dunes) wanda aka ɗauka sannan aka ajiye ta iska. An halicce su ne a ƙarƙashin yanayin sanyi, yanayin periglacial a ƙarshen shekarun kankara na Weichselian da Würm, watau kusan fiye da shekaru 10,000 da suka gabata. Ci gaban su a lokacin bayan lokacin sanyi ya sami rinjaye sosai daga bil'adama.

Misali mafi kyau na irin wannan yashi na nahiyar shine Deliblato Sands wanda wani lokacin ake kira "Sahara na Turai". Yafi yawa gandun daji ne a yau, kuma yashi mai budewa yana da wuya, kodayake yashi har yanzu yana motsawa (sannu a hankali fashewa).

 Arewacin Fennoscandia

A arewacin Sweden akwai dunes da yawa marasa aiki. Wadannan dunes an kafa su ne a cikin yanayin Holocene periglacial lokacin da Weichsel Ice Sheet ke janyewa. A halin yanzu ƙananan dunes na parabolic suna samuwa a arewacin Sweden saboda sake sanya dunes da suka lalace. Kamar yadda aka rubuta ta hanyar dune stratification iska da ta samar da mafi girma da tsofaffi dunes ya hura daga arewa maso yamma.

Hakanan ana iya samun dunes na ciki a cikin Finnish Lapland arewacin Arctic Circle da kuma Finnmark na Norway.

 Manazarta 

Rukuni:Shafuka masu fassarorin da ba'a duba ba