Plucking (glaciation)

Plucking, wanda kuma ake kira quarrying, wani abu ne na glacial wanda ke da alhakin yanayin yanayi da rushewa ɓangarorin dutse, musamman manyan "ginshiƙan haɗin gwiwa". Wannan yana faruwa a cikin wani nau'in ƙanƙara da ake kira "kwari mai kankara". Yayin da kankara ke motsawa a kwarin, rikici yana haifar da kankara na kankara don narkewa da shiga cikin haɗin gwiwa (cracks) a cikin dutse. Ayyukan daskarewa da narkewar kankara suna fadada, suna fadadawa, ko kuma suna haifar da ƙarin raguwa a cikin dutse yayin da yake canza girma a fadin canjin kankara / ruwa (wani nau'i na hydraulic wedging), sannu a hankali yana sassauta dutse tsakanin haɗin gwiwa. Wannan yana samar da manyan duwatsu da ake kira tubalan haɗin gwiwa. A ƙarshe waɗannan tubalan haɗin gwiwa sun ɓace kuma sun makale a cikin kankara.

Ta wannan hanyar, an haɗa cirewa da sake fasalin. Duwatsu na kowane girman zasu iya zama makale a kasan kankara. An "rufe" tubalan haɗin gwiwa har zuwa mita uku kuma an kai su. Wadannan raguwar dutse da aka kwashe na iya haifar da Abrasion tare da dutse da ganuwar da ta biyo baya. Plucking kuma yana haifar da alamun chatter, ƙuƙwalwar ƙuƙwalwa da aka bari a kan dutse ko wasu saman dutse. Gudun kankara duka suna amfani da fashewar da ta riga ta kasance a cikin dutse kuma suna buƙatar ci gaba da fashewa don kula da sake zagayowar rushewa. Gudun kankara ya fi mahimmanci inda dutsen ya haɗu sosai ko ya karye ko kuma inda ya ƙunshi jiragen gado da aka fallasa, saboda wannan yana ba da damar narkewar ruwa da clasts su shiga cikin sauƙi.

Plucking na bedrock kuma yana faruwa a cikin koguna masu tsawo, kuma yana da kamanceceniya da yawa tare da misalai na glacial. A irin waɗannan lokuta, raguwa da rarraba tubalan ya bayyana ne sakamakon haɗuwa da (1) sinadarai da yanayin jiki tare da haɗin gwiwa, (2) ƙuƙwalwar ruwa da ƙananan raguwar dutse ke shiga cikin tsagewar da ke akwai, (3) yaduwar fashewa daga damuwa da tasirin manyan clasts da suka riga sun kasance a cikin sufuri ta kogi, kuma mai yiwuwa (4) yaduwar da aka fitar ta hanyar karkatar da sakamakon bambancin matsin lamba a cikin ruwa a lokacin ambaliyar ruwa. Ana ɗaukar tubalan da aka saki ta hanyar ruwa mai saurin gudana a lokacin manyan ambaliyar ruwa, kodayake an yi imanin cewa motsi ba shi da inganci sosai fiye da ikon da ya dace da kankara don ɗaukar tubalan a ƙarƙashin kankara.

## Hanyoyin da ake amfani da su
Gudun kankara ya dogara da yawan damuwa da aka yi a kan wani clast rufe da kankara. Wannan dangantakar ita ce ma'auni tsakanin damuwa da aka yi a kan clast da matsin lamba na al'ada a kan clasta ta jikin kankara. Plucking yana ƙaruwa inda akwai raguwa a cikin gado na dutse. Yayin da kankara ke gangarowa a kan dutse, makamashi daga friction, matsin lamba ko zafi na geothermal yana haifar da ruwan da ya narke don shiga cikin sarari tsakanin duwatsu. Wannan tsari, wanda aka sani da ƙanƙara, yana mai da hankali kan tsarin dutse yayin da ruwa ke fadada lokacin da ya daskare. Tasirin daga manyan clasts da aka ɗauka a cikin gado na iya haifar da ƙarin damuwa ga dutse. Bugu da ƙari, ana iya ganin cirewa a matsayin tsarin ra'ayoyi mai kyau wanda karuwar aikin dutse da aka cire daga shimfidar wuri da aka jawo a cikin kankara yana haifar da karyewar sikelin da ya fi girma a kan kan kankara saboda nauyin nauyi na karfi da ke turawa ƙasa a kan gadon dutse.

## Rushewar inji
Gudun kankara shine babban hanyar wasu ƙananan ƙwayoyin ƙwayoyin cuta na ƙwayoyin halitta kamar su striation, Abrasion da glacial polishing. Mafi nauyi da nauyin sediment, mafi matsananciyar lalacewar shimfidar wuri. Rushewar ya dogara da yawan ruwa da saurin sa, girman clast da ƙarfinsa tare da alaƙa da kwanciyar hankali na gangaren.

### Yankin ƙanƙara
Dutse wanda ya kasance mai fama da rushewar kankara sau da yawa zai nuna tsarin tsagewa wanda dutsen ya bayyana a ciki. Tsawon layi daya zai rufe dutsen kuma ya nuna bayyanar wani abu da aka ja shi a samansa. Kodayake striations na iya samuwa a kan kowane irin dutse, yawanci suna nan a kan dutse mai ɗorewa kamar quartzite ko dutse inda ake kiyaye hanyoyin rushewa. Striations, saboda yanayin lalacewa, na iya gaya wa masana ilimin ƙasa hanyar da motsi na kankara.

### Gyara
Gishiri na kankara shine sakamakon clasts da aka saka a cikin kankara na kankara wanda ke wucewa a kan dutse kuma yana niƙa a saman dutsen zuwa wuri mai santsi. Ƙananan duwatsun da aka jawo ta hanyar cirewa suna aiki kamar takarda zuwa gangaren tudu. Wannan yana haifar da kusan madubi kamar farfajiyar a cikin dutse. Yaren mutanen Poland yana nuna wani tsari na baya-bayan nan kamar yadda sau da yawa yake ɓacewa ga yanayin dutse.

## Gishiri har zuwa
Za'a iya ajiye tubalan haɗin gwiwa da raguwar dutse waɗanda aka kwashe su kuma aka ɗauke su a kan dutse kamar yadda har zuwa. Wannan yana haifar da dukkanin siffofin glacial masu tasowa kamar su moraines, roche moutonnées, glacial erratics da drumlin fields.

## Manazarta