Zamanin kankara na karshe da yadda mutane suka zo Amurka

Ana amfani da mu, da rashin alheri, don ganin sakamakon canjin yanayi. Duniya mai ƙara zafi da sakamakon ci gaba da ƙaruwa a hankali da ci gaba. Yawancin abubuwa da muke gani suna faruwa a yau, ba haka suke ba a da. Gidanmu, Duniyar Duniya, yana da lokutan yanayi mai zafi da sanyi. Tarihin ɗan adam ya isa mana mu ɗanɗana ƙarshen kankara. Wanda kuma ya taka muhimmiyar rawa a tarihinmu a fadada yawan mutane a duniya. Ofaya daga cikin waɗancan matakan nasa shine babu shakka zuwan mutane zuwa nahiyar Amurka.

Kuma wannan shine Akwai ra'ayoyi da yawa game da yadda mutane suka zo Amurka. Daga cikin su duka, ɗayan mafi sahihanci kuma tabbatacce shine cewa sun ratsa ta hanyar "Beringia Bridge". Kuma aka sani da kawai Beringia. Dukkanin da'irar ja a cikin hoton tana nuna gadar macro wacce ta samo asali shekaru 40.000 da suka gabata. Ana lissafin cewa dan Adam na iya ratsa shi shekaru dubu 20.000 da suka gabata yana tafiya, yayin da matakin teku ya fadi mita 120.

Yaya duniyarmu take a lokacin?

Iceanƙarar ta rufe babban yanki. Kimanin sau uku fiye da matsakaicin na yanzu. Matsakaicin zafin duniyar mu yakai 10ºC ƙasa da na yanzu 15 averageC. Gadar Beringia, wacce ita ce bangaren da aka yiwa alama da jan da'irar, ta samar da hanyar tsallaka nahiyoyin biyu. A lokacin lokacin kankara, matakin teku ya sauka. Hakanan, yankunan da ke da ruwa suna ƙarfafawa. Kamar yadda muka yi tsokaci, glaciers sunfi yawa yawa. Kuma ga wayewar makiyaya, ta kasance mashigar sabuwar duniya.

Sun ratsa yankin arewa maso gabashin Asiya, Rasha ta yanzu, suna wucewa ta Gadar Beringia, Tekun Bering na yanzu, sun isa Amurka ta Arewa maso yamma, Alaska ta yanzu. An samo kayan aiki daga kakanninmu, irin na al'adun da suke dasu. Abubuwa iri ɗaya, don amfanin ɗaya, yanke kuma anyi su iri ɗaya.

Thearshen zamanin kankara

5.000 shekaru daga baya, kimanin shekaru 15.000 da suka wuce, zamanin kankara ya ƙare. Ba zato ba tsammani, zafin jiki ya tashi a cikin shekaru 1 zuwa 3 masu zuwa. Dangane da bayanan masana kimiyyar burbushin halittu, waɗanda zasu iya nazarin canje-canje a cikin yanayin shekaru 125.000 da suka gabata a cikin kankara tare da ƙwarewa na ƙwarai. Kazalika ta wata hanyar saboda sassaucin ra'ayi na CO2 wanda aka adana a Antarctica, kamar yadda bincike da bincike na baya-bayan nan suka nuna. Cibiyar Kimiyyar Muhalli da Fasaha ta Barcelona ta halarci ƙarshen.

Duniyar ta fara sake kafa kanta. Makiyayanmu marasa tsoro don neman rayuwa, sun ci gaba da tafiya daga Arewa zuwa Kudu a duk faɗin Amurka. Gilashi sun fara ja da baya, matakin teku yana ta sake haurawa, kuma tare da shi, hanyar da aka rufe duk nahiyoyin biyu tun daga nan. Sai kawai a ɗan fiye da shekaru 500 da suka gabata, kuma a hukumance, wayewar wayewar zata sake saduwa, bayan ci gaba ta hanyoyi daban-daban.

Paleoclimatology. Ice dabaru da asirin

Masanan burbushin halittu suna amfani dashi dabaru daban-daban don cire bayanan paleoclimates. Misali, kayan ciki, inda daga ilmin sunadarai na duwatsu ko burbushin siɗa don cire fauna, flora, plankton, pollen ... Wata dabara ita ce dendroclimatology, inda ake ciro bayanai daga zoben bishiyoyin da aka yi man ja. Murjani don ganin Tº na yanayin ƙasa wanda yake cikin teku. Fuskokin ƙasa inda za'a iya hango matakin teku, yana nuna manyan canje-canje na paleoclimatic. Kuma game da kankara, mafi yawan amfani dasu yawanci sune masu zuwa:

paleopollen

Tsakanin shimfidar kankara da aka kafa da kuma tarawa shekara-shekara, zamu iya samun paleopolen. Wannan yana ba da damar kimanta wane irin ciyayi ne a waɗancan shekarunKo da a ciki akwai toka daga wani dutsen da ya yi aman wuta.

Air

Jirgin da aka kama a cikin hanyar microbubbles asalin asalin bayanai ne saboda abin da yake samarwa wanda ke taimakawa wajen tantance wane irin yanayi ne ya kasance a waccan lokacin.

Isotopes na barga

Ta hanyar danshin ruwa, da dan bambanci kadan a cikin isotopes barga waɗanda aka adana a cikin kankara saboda nauyinsu ƙasa da hydrogen da oxygen, an sami daidaito tsakanin lokaci daban-daban.