Chigwa cha Glacier

glacier ku Iceland

Zigwa za madzi oundana, zomwe zimadziwikanso kuti zigwa za ayezi, zimatanthawuza zigwa zomwe madzi oundana akuluakulu amazungulira kapena kuzunguliridwa kamodzi, ndikusiya mawonekedwe owoneka bwino a madzi oundana. A chigwa cha glacier Ndikofunikira kwambiri pamitundu yosiyanasiyana yazachilengedwe komanso kulinganiza kwachilengedwe.

Pachifukwa ichi, tikukuuzani zonse zomwe muyenera kudziwa zokhudza chigwa cha glacial, makhalidwe ake a geomorphology.

Kodi chigwa cha glacial ndi chiyani

chigwa cha cantabrian

Zigwa za madzi oundana, zomwenso zimatchedwanso kuti mitsinje ya madzi oundana, ndi zigwa zomwe tingapeze kuti zasiya mitundu yothandiza ya madzi oundana.

Mwachidule, zigwa za madzi oundana zili ngati madzi oundana. Zigwa za glacial zimapangika pamene madzi oundana ambiri amawunjikana mu glacial cirques. Madzi oundana ochokera m'munsi mwake amapita pansi pa chigwacho, ndipo pamapeto pake amakhala nyanja.

Chimodzi mwazinthu zazikulu za zigwa za glacial ndikuti ali ndi gawo lofanana ndi mtanda, ndichifukwa chake amatchedwanso ma glacial troughs. Mbali imeneyi ndi mbali yaikulu yomwe imalola akatswiri a sayansi ya nthaka kusiyanitsa mitundu ya zigwa zomwe madzi oundana ambiri amatsetsereka kapena kutsetsereka konse. Zizindikiro zina za zigwa za madzi oundana ndizo mavalidwe awo ndi kukumba mopitirira muyeso, chifukwa cha kugunda kwa ayezi ndi kukokera kwa zinthu.

Madzi oundana akale pa Dziko Lapansi anaika zinthu zimene poyamba zinakokoloka ndi madzi oundana. Zida izi ndizosiyana kwambiri, ndipo nthawi zambiri zimapanga zosiyana mitundu ya moraines, monga moraines pansi, moraines pambali, moraines ogwa, ndipo choyipa kwambiri, pakati pomwe nyanja yotchuka ya glacial nthawi zambiri imapangidwa. Zitsanzo zomalizazi ndi nyanja zamchere zomwe tingapeze m'mphepete mwa mapiri a European Alps (otchedwa Como, Mayor, Garda, Geneva, Constanta, etc.) kapena m'madera ena apakati pa Sweden ndi ena ambiri.

Mphamvu za chigwa cha glacial

mawonekedwe a glacial Valley

Pankhani ya kukokoloka kwa madzi oundana, m’pofunika kunena kuti madzi oundana amakokoloka kwambiri ndipo amatha kukhala ngati malamba onyamula zinthu zamisinkhu yonse yoperekedwa ndi malo otsetsereka, kuwatengera ku zigwa.

Komanso, pali madzi ambiri osungunuka m'madzi oundana, yomwe imatha kuyendayenda mothamanga kwambiri m'ngalande mkati mwa madzi oundana, kukweza zinthu pansi pa madzi oundana, ndipo mafunde apansi pamadziwa ndi othandiza kwambiri. Zomwe zimanyamula zimapanga abrasion, ndipo miyala yomwe ili mkati mwa madzi oundana imatha kuphwanyidwa kukhala osakaniza a silt ndi ufa wadongo.

Ma glaciers amatha kugwira ntchito m'njira zitatu zazikulu ndipo ndi izi: glacial chiyambi, abrasion, kukankha.

Pokumba miyala yosweka, mphamvu ya madzi oundana imatha kusuntha ndi kukweza miyala ikuluikulu yosweka. M'malo mwake, mawonekedwe akutali a bedi la glacier ndi osakhazikika, okhala ndi madera omwe amakula ndikuzama ngati mitsinje kapena mitsinje, yomwe imakulirakulira ndi kukumba mopitilira mwala wosakumba kwambiri komanso wosamva. Malowa amachepetsedwa ndipo amatchedwa latch kapena pachimake.

Pamtanda, mapulaneti amapangidwa mu miyala yamphamvu yomwe imaphwanyidwa pamtunda wina wake, wotchedwa mapewa. Abrasion imaphatikizapo kupeta, kupala, ndi kupera pamiyala ndi tizidutswa ta miyala tomwe timakhala ndi ayezi. Izi zimapanga zokopa ndi grooves. Popukuta, ndi zinthu zabwino kwambiri, monga sandpaper pamwala.

Pa nthawi yomweyo, chifukwa cha abrasion, miyala imaphwanyidwa, kutulutsa dongo ndi silt, yotchedwa ice powder chifukwa cha kukula kwake kwambewu, yomwe ili m'madzi osungunuka ndipo imakhala ndi maonekedwe a mkaka wosakanizidwa.

Mwamphamvu, madzi oundana amanyamula ndikukankhira kwa iwo okha zinthu zowola zomwe zimaphwanya ndikusintha monga tafotokozera pamwambapa.

mitundu ya kukokoloka

chigwa cha glacier

Ena mwa iwo ndi odziwika ma circus, tarn, zitunda, nyanga, khosi. Popanga zitsanzo za zigwa za glacial, zimakonda kukhala m'zigwa zomwe zinalipo kale, zomwe zimakula ndikuzama mu mawonekedwe a U. Glaciers anakonza ndi kuphweka zokhotakhota za zigwa zoyambirira ndi zowonongeka za rock spurs, kupanga zazikulu za triangular kapena truncated spurs.

M'mawonekedwe a nthawi yayitali a chigwa cha glacial, mabeseni ophwanyika ndi zowonjezera zimatsatana, kupanga maunyolo a nyanja omwe amalandira dzina la makolo athu pamene mabeseni amadzaza madzi.

Kwa iwo, Chigwa cha Hanging Valley ndi chigwa chakale chomwe chimadutsa pamtunda waukulu wa madzi oundana. Amafotokozedwa chifukwa kukokoloka kwa madzi oundana kumadalira kukhuthala kwa madzi oundana, ndipo madzi oundana amatha kuzama m’zigwa zawo osati mitsinje yake.

Fjords imapanga pamene madzi a m'nyanja amalowa m'zigwa za glacial, monga za ku Chile, Norway, Greenland, Labrador, ndi fjords yakumwera ku Alaska. Nthawi zambiri amagwirizanitsidwa ndi zolakwa ndi kusiyana kwa lithological. Amafika mozama kwambiri, monga njira ya Messier ku Chile, yomwe Kuzama kwake ndi 1228 metres. Izi zikhoza kufotokozedwa ndi kukumba mopitirira muyeso kwa madzi oundana akukokoloka m'munsi mwa nyanja.

Kunyezimira kungathenso kutsanzira miyala yomwe imapanga miyala yonga nkhosa, yomwe malo ake osalala, ozungulira amafanana ndi gulu la nkhosa zowonedwa pamtunda. Amakhala kukula kwake kuchokera pa mita imodzi mpaka makumi a mita ndipo amalumikizana motsatira njira ya ayezi. Mbali ya kasupe wa ayezi imakhala ndi mawonekedwe osalala chifukwa cha mphamvu yakupera, pamene mbali inayo ili ndi mbiri ya angular ndi yosasinthika chifukwa cha kuchotsa miyala.

Mitundu yodzikundikira

Madzi oundana atsika kuyambira nthawi ya ayezi yomaliza, pafupifupi zaka 18.000 zapitazo, kusonyeza mpumulo wobadwa nawo m'magawo onse omwe adakhala nawo m'nyengo yachisanu yomaliza.

Ma depositi a glacial ndi madipoziti opangidwa ndi zinthu zomwe zimayikidwa mwachindunji ndi madzi oundana, opanda mawonekedwe ozungulira komanso omwe zidutswa zake zimakhala ndi mizere. Kuchokera pakuwona kukula kwa tirigu, ndizosiyana kwambiri, kuyambira ufa wa glacial kupita kumagulu osakhazikika omwe amanyamulidwa makilomita 500 kuchokera kudera lawo, monga omwe amapezeka ku Central Park ku New York; ku Chile, ku San Alfonso, mu kabati ya Maipo. Ma depositiwa akaphatikizana, amapanga tillites.

Mawu akuti moraine amagwiritsidwa ntchito ku mitundu ingapo yomwe imakhala ndi mapiri. Pali mitundu ingapo ya moraines ndi mapiri aatali otchedwa drumlins. Moraine wakutsogolo ndi mulu womwe uli kutsogolo kwa madzi oundana omwe amamanga pamtunda pomwe madzi oundana amakhala okhazikika pamalo amodzi kwa zaka kapena zaka zambiri. Ngati madzi oundana akupitirirabe, matope adzapitiriza kuwunjikana pa chotchinga chimenechi. Ngati madzi oundanawo achepa, dzira la moraine loyenda pang'onopang'ono, lotchedwa basal moraine, limayikidwa, monga m'madambo a m'dera la Nyanja Yaikulu ku United States. Kumbali ina, ngati madzi oundanawo apitirizabe kubwerera m'mbuyo, nsonga yake ingakhazikikenso, n'kupanga moraine wobwerera.

Mitsinje yam'mbali imakhala yofanana ndi madzi oundana a m'zigwa ndipo imanyamula matope m'mphepete mwa zigwa, ndikuyika zitunda zazitali. Mapangidwe a moraine apakati pomwe ma moraine awiri am'mbali amakumana, monga pakulumikizana kwa zigwa ziwiri.

Ma Drumlins ndi mapiri osalala, opyapyala omwe amapangidwa ndi miyala ya moraine yomwe imayikidwa ndi madzi oundana a kontinenti. Amatha kufika mamita 50 ndi kutalika kwa kilomita, koma zambiri ndi zazing’ono. Ku Ontario, Canada, amapezeka m’minda yokhala ndi ng’oma zambirimbiri. Pomaliza, mawonekedwe opangidwa ndi tizidutswa tating'ono ta glacial monga kame, kame terraces ndi eskers amadziwika.

Ndikukhulupirira kuti ndi chidziwitsochi mungaphunzire zambiri za chigwa cha glacial ndi makhalidwe ake.


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