Ukuthandana Okuphelele Kwezinto Zasendulo
Ukuqopha usuku oluphelele emvubukulweni yimizamo yokuthola ubudala bokutholakala, ungqimba lomhlabathi, noma isenzakalo esidlule ngesikhathi sekhalenda esinembile—isibonelo, “eminyakeni engu-2.500 eyedlule” noma “cishe ngo-500 BC–200 AD.” Ngokungafani nokuqopha usuku oluhlobene, olubala nje “omdala” kanye “nomncane,” ukuqopha usuku oluphelele kuzama ukwabela unyaka noma ububanzi beminyaka ethile. Empeleni, abavubukuli abavamile ukufeza ukuqiniseka okuphelele kuze kube usuku noma unyaka ngaphandle komongo owengeziwe, kodwa izindlela zesayensi zanamuhla zivumela ukulinganisa iminyaka okunembile ngezinga elilinganiselwe lokungaqiniseki.
Kungani ukuqomisana okuphelele kubalulekile?
Ngaphandle kokuqopha usuku oluphelele, izindaba zomlando wesintu beziyoba nzima ukuzakha ngokulandelana kwezikhathi nokuqhathanisa kuzo zonke izifunda. Isibonelo, singanquma ukuthi ubuchwepheshe bezolimo buqale nini ukuthuthuka esifundeni, lapho kwenzeka khona ukufuduka okukhulu, noma lapho indawo ishiywe khona ngenxa yenhlekelele yemvelo noma ingxabano. Ukuqopha usuku oluphelele kusiza futhi ukuhlola imibono: ingabe izinguquko ezindleleni zobumba zenzeke ngesikhathi esifanayo nokushintsha kwesimo sezulu? Ingabe ukwakhiwa kwezakhiwo ezinkulu kwenzeka ngesikhathi esisodwa ezifundeni eziningana, noma ingabe zahlukile?
Ngaphezu kwalokho, ukuqopha usuku ngokuphelele kunikeza isisekelo sokuxhumanisa idatha yemivubukulo neminye imikhakha efana ne-geology, i-paleoclimatology, i-biology anthropology, kanye nomlando obhaliwe. Ngezibalo zokuqopha ezicacile, okutholakele kwemivubukulo kungafakwa "esikhathini somhlaba wonke".
Izimiso ezijwayelekile: isampula, umongo, kanye nokungaqiniseki
Impumelelo yokuqopha isikhathi ngokuphelele inqunywa yizinto ezintathu: ikhwalithi yesampula, umongo wezinto zakudala, kanye nendlela ukungaqiniseki okuphathwa ngayo.
1. Ikhwalithi yesampula: izinto ezizohlolwa kumele zihambisane nesenzakalo esinqunywa ubudala baso. Izinkuni ezisetshenziswe ukwakha indlu, isibonelo, zifaneleka kakhulu kunezinkuni ezithwalwa yizikhukhula bese zilahlwa kamuva.
2. Umongo: amasampula kumele avele ongqimbeni noma isici esihlukile (isb., indawo ephansi, umgodi ongemuva, ithuna, noma indawo yomlilo) futhi angaxutshwa nemisebenzi yezinto eziphilayo, ukumba kwasendulo, noma izinqubo zemvelo.
3. Ukungaqiniseki (iphutha/ububanzi): Imiphumela yokuqomisana okuphelele cishe njalo iwububanzi, isibonelo, kusukela ngo-980 kuya ku-1040 AD ezingeni elithile lokuzethemba. Izazi zemivubukulo kumele zihumushe le datha ngendlela engenzeka, hhayi njengenombolo eyodwa, "eqondile".
Izindlela eziyinhloko zokuthandana ngokuphelele
1. I-Radiocarbon (i-Carbon-14)
Indlela ye-radiocarbon ingenye yezindlela ezaziwa kakhulu kwezokumbiwa kwezinto zakudala. Isimiso sayo sincike ekuboleni kwe-isotope ye-carbon enemisebe (C-14) ezintweni eziphilayo. Ngesikhathi into ephilayo isaphila, ishintshana njalo nge-carbon nendawo ezungezile. Ngemva kokufa, lokhu kushintshana kuyama, futhi i-C-14 iqala ukubola ngesivinini esithile (ingxenye yokuphila yeminyaka engaba ngu-5.730). Ngokulinganisa i-C-14 esele, ososayensi bangakwazi ukubala iminyaka yokufa kwale nto ephilayo.
Izinto ezingahlolwa zifaka phakathi amalahle, ukhuni, amathambo, imbewu, izindwangu zemvelo zefayibha, kanye nezinye izinsalela zezinto eziphilayo. Kodwa-ke, ukuqoqwa kwe-radiocarbon akunikezi ngokuqondile "unyaka wekhalenda" ongavuthiwe; imiphumela idinga ukulungiswa ngokulinganisa ngoba amazinga e-C-14 asemoyeni ayashintshashintsha ngokuhamba kwesikhathi. Ukulinganisa kwenziwa kusetshenziswa ijika elijwayelekile (ngokwesibonelo, elisekelwe ezindongeni zemithi).
Izinzuzo zokuqopha i-radiocarbon: ukusebenza okubanzi, isikhathi eside (kuze kube ngamashumi ezinkulungwane zeminyaka). Okubi: ukungenwa kalula ukungcola, kudinga ukulinganiswa, futhi akusebenzi ezintweni ezindala kakhulu ezingaphandle kwemingcele yendlela.
2. I-Dendrochronology (Izindandatho Zesihlahla)
I-Dendrochronology isebenzisa amaphethini endandatho yokukhula yonyaka yezihlahla. Izihlahla ezikhula esifundeni esithile zizobonisa amaphethini obukhulu bendandatho obuhlobene nezimo zezulu. Ngokufanisa amaphethini endandatho yamasampula ezinkuni zakudala nochungechunge lwezindawo zokubhekisela, ubudala bezinkuni bunganqunywa ngokunemba konyaka, futhi ngezinye izikhathi ngisho nangesizini.
Le ndlela inamandla kakhulu uma uchungechunge olude lokubhekisela lutholakala futhi isampula yokhuni inamasongo anele. I-Dendrochronology nayo idlala indima ebalulekile ekulinganisweni kwe-radiocarbon, njengoba amasongo esihlahla enikeza izinsuku zekhalenda ezingaqhathaniswa nemiphumela ye-C-14.
Imikhawulo: isebenza kuphela okhunini olugcinwe kahle olunezindandatho ezicacile; akuzona zonke izifunda ezinesizindalwazi esiphelele sezindandatho zezihlahla.
3. I-Thermoluminescence (TL) kanye ne-Optically Stimulated Luminescence (OSL)
Indlela yokukhanya isetshenziselwa ukunquma ukuthi i-mineral yagcina nini ukudalulwa ekushiseni okuphezulu noma ekukhanyeni.
– I-Thermoluminescence (TL) ivame ukusetshenziswa ezintweni zobumba noma amatshe ashisiwe (isibonelo, ngesikhathi senqubo yokudubula izitsha zobumba). I-TL ilinganisa amandla “abanjwe” kumakristalu amaminerali; uma eshiswa elabhorethri, la mandla akhishwa njengokukhanya. Ibonisa isikhathi kusukela ekudubuleni kokugcina.
– I-Optically Stimulated Luminescence (OSL) ivame ukusetshenziselwa izinsalela zesihlabathi noma zenhlabathi. I-OSL ilinganisa ukuthi izinhlayiya zamaminerali zagcina nini ukudalulwa elangeni ngaphambi kokungcwatshwa.
Izinzuzo ze-TL/OSL: zingasetshenziswa ezintweni ezingenazo izinto eziphilayo; ziwusizo ekutholeni isikhathi sokungcola kanye nomsebenzi wokushisa. Imikhawulo: idinga izinqubo zokuthatha amasampula ngokucophelela ukuze kugwenywe ukuchayeka ekukhanyeni (ikakhulukazi i-OSL), futhi ukuhumusha kuncike emlandweni wokuchayeka endaweni ezungezile.
4. I-Potassium-Argon (K-Ar) kanye ne-Argon-Argon (Ar-Ar)
Izindlela ze-K-Ar kanye ne-Ar-Ar zisetshenziswa ikakhulukazi ezimweni zasendulo kakhulu futhi maqondana nezinto zentaba-mlilo. I-Potassium-40 iyabola ibe yi-argon-40. Ngenxa yokuthi i-argon iyigesi, iba "ibhajwe" kumaminerali athile njengoba amatshe entaba-mlilo epholile. Ngokulinganisa isilinganiso se-potassium ne-argon, ubudala bedwala bungatholakala.
Le ndlela ibalulekile ezindaweni zakudala kakhulu, ikakhulukazi lezo ezihlobene nokuziphendukela kwemvelo kwabantu, ngoba ingasukela ezingqimbeni zomlotha wentaba-mlilo ezizungeze izinsalela noma izinto zobuciko.
Izinzuzo: ifanelekela izikhathi ezinde kakhulu (amakhulu ezinkulungwane kuya ezigidini zeminyaka). Okubi: ayisebenzi ezindaweni ezingenayo indawo enentaba-mlilo; ifaneleka kakhulu kwi-geochronology kunezinto zobuciko zansuku zonke.
5. Uchungechunge lwe-Uranium (Uchungechunge lwe-U)
Ukuqomisana kochungechunge lwe-uranium kusebenzisa ukubola kwe-uranium kuma-isotope ayo endodakazi (njenge-thorium). Le ndlela ingasetshenziswa ukuthola i-calcite emihumeni (ama-stalagmite/ama-stalactites), ama-coral, futhi ngezinye izikhathi amathambo noma amazinyo ngaphansi kwezimo ezithile.
Emivubukulweni, uchungechunge lwe-U luvame ukuba usizo ezimweni zemihume, isibonelo ukunquma ubudala bezingqimba ze-calcite ezimboza imidwebo yemihume noma izinsalela zemivubukulo ezinhlangothini.
6. I-Archaeomagnetism kanye ne-Paleomagnetism
Insimu yamagnetic yomhlaba ishintsha kancane kancane ngokuhamba kwesikhathi. Izinto ezifudumalayo (njengezitofu, izitofu, noma izitini) zingaqopha "isiqondiso" namandla ensimu yamagnetic njengoba iphola. Ngokuqhathanisa leli rekhodi lamagnetic nama-geomagnetic change curves esifunda, iminyaka yokusha ingalinganiselwa.
Lokhu kuwusizo kakhulu uma indawo inezakhiwo zokushisa ezisekhona futhi indawo ine-geomagnetic reference curve enhle.
Izindlela zokuhlanganisa: unxantathu wokulandelana kwesikhathi
Abavubukuli abavami ukuthembela endleleni eyodwa. Ukuze bandise ukuthembeka, bahlanganisa amasu amaningana, njengokuthola idatha ye-radiocarbon kusuka kumalahle omlilo, ukuthola idatha ye-OSL kusuka ezitsheni ezimboze phansi, kanye ne-dendrochronology evela ezingodweni zokwakha. Uma imiphumela isekelana, ukuzethemba ngokulandelana kwezikhathi kuyanda. Uma kuphikisana, kubonisa inkinga: ukungcola kwesampula, ukuxuba ungqimba, "umphumela wokhuni oludala," noma izehlakalo zokuphazamiseka ngemuva kokufakwa.
Ngaphezu kwalokho, izindlela zezibalo ezifana nokumodela kwe-Bayesian zivame ukusetshenziswa ukuhlanganisa idatha yokuqopha nolwazi lwe-stratigraphic (ukulandelana kwezingqimba). Lokhu kuvumela isikhathi ukuthi sincishiswe futhi sakhiwe ngendlela engokoqobo ngaphakathi komongo wokumba.
Izinselele ezivamile ekuqomisaneni ngokuphelele
Ezinye izinselele ezivame ukuvela zifaka:
– Ukungcola: izinto zesimanje zingena kumasampula amadala (noma okuphambene nalokho), zishintsha imiphumela.
– Inkinga yokumelwa: okubhalwe phansi “yizinto ezibonakalayo,” hhayi njalo “isenzakalo” esifuna ukusazi. Isibonelo esivamile: ukhuni oluvela emthini omdala lunganikeza ubudala obudala kunangesikhathi lwakhiwa.
– Imikhawulo yezinto ezibonakalayo: akuzona zonke izindawo ezinezinsalela zezinto eziphilayo, ukhuni olugciniwe, noma izinto zentaba-mlilo.
– Umongo ophazamisekile: umsebenzi wezilwane, izimpande, ukumba kabusha, noma izikhukhula kungasusa izinto ezidaliwe endaweni yazo yokuqala.
I-Penutup
Ukuqopha usuku ngokuphelele kuyisisekelo esibalulekile sezinto zakudala zanamuhla ngoba kuvumela ukwakhiwa kabusha kwesikhathi esidlule ngokulandelana kwesikhathi nokuhlolwayo. Besebenzisa izindlela ezahlukahlukene—ukuqopha usuku nge-radiocarbon, i-dendrochronology, ukukhanya, ukuqopha usuku nge-K-Ar/Ar-Ar, ukuqopha usuku nge-U, kanye ne-archaeomagnetism—izazi zemivubukulo zingalinganisa iminyaka yezinto ezitholakele kusukela emakhulwini kuya ezigidini zeminyaka. Kodwa-ke, “okuphelele” akusho ukuthi ngaphandle kokungaqiniseki. Amandla ale ndlela atholakala ezilinganisweni zayo zesayensi ezicacile neziphindaphindwayo, ezihlala zifundwa kumongo we-stratigraphy kanye nobunye ubufakazi. Ngokuhlanganisa izindlela kanye nokuhlolwa okubucayi kwamasampula, ukuqopha usuku ngokuphelele kusisiza siqonde ukuthi abantu babumba nini futhi kanjani isiko, ubuchwepheshe, kanye nendawo esiyithola namuhla.
