Gishiri na Quaternary

QuaterNa glaciation, wanda aka fi sani da Pleistocene glaciation. Kodayake masana ilimin ƙasa sun bayyana wannan lokacin har zuwa yanzu a matsayin "lokacin ƙanƙara", a cikin al'adun gargajiya wannan kalmar yawanci tana nufin lokacin glacial na baya-bayan nan, ko kuma zamanin Pleistocene gabaɗaya. Tun da Duniya har yanzu tana da kankara, masu ilimin ƙasa suna la'akari da Quaternary glaciation don ci gaba, kodayake a halin yanzu a cikin lokacin interglacial.

A lokacin Quaternary glaciation, kankara ya bayyana, yana fadada a lokacin glacial da kuma kwangila a lokacin interglacial. Tun daga ƙarshen lokacin glacial na ƙarshe, kawai kankara na Antarctic da Greenland sun tsira, yayin da wasu takalma da aka kafa a lokacin glacial, kamar Laurentide Ice Sheet, sun narke gaba ɗaya. 
Babban tasirin glaciation na Quaternary sun kasance rushewa ƙasa da kuma zubar da kayan; gyare-gyaren tsarin kogin; sauka da miliyoyin tabkuna, gami da ci gaban tabkuna masu ruwan sama da ke nesa da gefen kankara; canje-canje a matakin teku; gyarewar isostatic na ɓawon duniya; ambaliyar ruwa; da isostatic iska. Gilashin kankara, ta hanyar ɗaga albedo (rashin hasken rana da aka nuna daga Duniya zuwa sararin samaniya), ya samar da mahimman ra'ayoyi don kara sanyaya yanayi. Wadannan tasirin sun tsara yanayin ƙasa da na teku da al'ummomin halittu.

Tsawon lokaci kafin glaciation na Quaternary, kankara na ƙasa ya bayyana sannan ya ɓace a cikin akalla wasu shekarun kankara huɗu. Za'a iya la'akari da glaciation na Quaternary a matsayin wani ɓangare na Late Cenozoic Ice Age wanda ya fara 33.9 Ma kuma yana ci gaba.

 Bincike 
An fara fahimtar shaidar Quaternary glaciation a cikin ƙarni na 18 da 19 a matsayin wani ɓangare na Juyin Juya Halin Kimiyya. A cikin ƙarni na ƙarshe, lura da yawa a fagen ya ba da shaida cewa kankara na nahiyar sun rufe manyan sassan Turai, Arewacin Amurka, da Siberia. An tattara taswirar siffofin glacial bayan shekaru da yawa na aikin gona ta daruruwan masana kimiyyar ƙasa waɗanda suka tsara wurin da daidaitawar drumlins, eskers, moraines, striations, da tashoshin rafi na glacial don bayyana girman kankara, jagorancin gudana, da tsarin tashoshin ruwa. Sun kuma ba da damar masana kimiyya su fassara tarihin ci gaba da yawa da kuma koma baya na kankara. Ko da kafin a yarda da ka'idar glaciation na duniya gabaɗaya, masu kallo da yawa sun fahimci cewa fiye da ci gaba ɗaya da koma baya na kankara sun faru.

 Manazarta