Chibwenzi Chokhazikika mu Zakale Zakale
Kufufuza nthawi yeniyeni mu kafukufuku wa zinthu zakale ndi kuyesa kudziwa zaka zomwe zapezeka, dothi losanjikiza, kapena chochitika chakale mu nthawi yeniyeni ya kalendala—mwachitsanzo, “zaka 2.500 zapitazo” kapena “pafupifupi 500 BC–200 AD.” Mosiyana ndi kusanthula nthawi yeniyeni, komwe kumangotchula “zaka zazikulu” ndi “zazing'ono,” kusanthula nthawi yeniyeni kumayesa kugawa chaka kapena zaka zinazake. Mwachidule, akatswiri ofufuza zinthu zakale nthawi zambiri samapeza chitsimikizo chokwanira mpaka tsiku limodzi kapena chaka popanda nkhani yowonjezera, koma njira zamakono zasayansi zimalola kuwerengera zaka molondola ndi kuchuluka kotsimikizika koyezeka.
N’chifukwa chiyani chibwenzi chenicheni chili chofunika?
Popanda kuwerengera nthawi yeniyeni, nkhani za mbiri ya anthu zingakhale zovuta kuzilemba motsatira nthawi ndi kuziyerekeza m'madera osiyanasiyana. Mwachitsanzo, titha kudziwa nthawi yomwe ukadaulo waulimi unayamba kukula m'dera linalake, pamene kusamuka kwakukulu kunachitika, kapena pamene malo ena anasiyidwa chifukwa cha masoka achilengedwe kapena mikangano. Kuwerengera nthawi yeniyeni kumathandizanso kuyesa malingaliro: kodi kusintha kwa mitundu ya miphika kunachitika panthawi yomweyi ndi kusintha kwa nyengo? Kodi kumanga nyumba za megalithic kunachitika nthawi imodzi m'madera angapo, kapena kodi kunasiyana?
Kuphatikiza apo, kuwerengera nthawi yeniyeni kumapereka maziko ogwirizanitsa deta ya zinthu zakale ndi maphunziro ena monga geology, paleoclimatology, biological anthropology, ndi mbiri yolembedwa. Ndi ziwerengero zomveka bwino za masiku, zomwe zapezeka m'mabwinja zimatha "kuyikidwa" mu nthawi yapadziko lonse lapansi.
Mfundo zazikulu: chitsanzo, nkhani, ndi kusatsimikizika
Kupambana kwa kusanthula kwa deti yeniyeni kumatsimikiziridwa ndi zinthu zitatu: mtundu wa zitsanzo, momwe zinthu zakale zimachitikira, komanso momwe kusatsimikizika kumayendetsedwera.
1. Ubwino wa chitsanzo: zinthu zomwe ziyenera kuyesedwa ziyenera kukhala zogwirizana ndi chochitika chomwe zaka zake zikudziwika. Mwachitsanzo, matabwa omwe amagwiritsidwa ntchito pomanga nyumba ndi oyenera kuposa matabwa omwe amanyamulidwa ndi kusefukira kwa madzi kenako n’kuikidwa m’nyumba.
2. Nkhani: zitsanzo ziyenera kuchokera ku gawo kapena mawonekedwe enaake (monga pamwamba pa nthaka, dzenje la positi, manda, kapena malo ophikira moto) ndipo zisasakanizidwe ndi zochitika zamoyo, kufukula zakale, kapena njira zachilengedwe.
3. Kusatsimikizika (cholakwika/kuchuluka): Zotsatira zenizeni za nthawi yopezera zaka pafupifupi nthawi zonse zimakhala pakati pa 980–1040 AD pamlingo winawake wodalirika. Akatswiri ofukula zinthu zakale ayenera kutanthauzira deta iyi mwanjira ina, osati ngati nambala imodzi, "yeniyeni".
Njira zazikulu zopezera chibwenzi chenicheni
1. Radiocarbon (Kaboni-14)
Njira ya radiocarbon ndi imodzi mwa njira zodziwika bwino kwambiri mu kafukufuku wa zinthu zakale. Mfundo yake imadalira kuwonongeka kwa isotope ya carbon radioactive (C-14) mu zinthu zachilengedwe. Pamene chamoyo chili ndi moyo, chimasinthasintha kaboni ndi chilengedwe chake nthawi zonse. Pambuyo pa imfa, kusinthaku kumasiya, ndipo C-14 imayamba kuwola pamlingo winawake (theka la moyo wa zaka pafupifupi 5.730). Poyesa C-14 yotsalayo, asayansi amatha kuwerengera zaka zomwe chamoyocho chimafa.
Zipangizo zomwe zingayesedwe zikuphatikizapo makala, matabwa, mafupa, mbewu, nsalu zachilengedwe, ndi zotsalira zina zachilengedwe. Komabe, kuwerengera kwa radiocarbon sikupereka mwachindunji "chaka cha kalendala" chosaphika; zotsatira zake ziyenera kukonzedwa kudzera mu calibration chifukwa milingo ya C-14 mumlengalenga imasinthasintha pakapita nthawi. Calibration imachitika pogwiritsa ntchito curve yokhazikika (monga, kutengera mphete za mitengo).
Ubwino wa kuwerengera nthawi ya radiocarbon: kugwiritsidwa ntchito kwakukulu, nthawi yayitali (mpaka zaka zikwi makumi ambiri). Zoyipa: zimakhala zosavuta kuipitsidwa, zimafuna kuyesedwa, komanso sizigwira ntchito pazinthu zakale kwambiri zomwe sizili ndi malire a njirayo.
2. Dendrochronology (mphete za Mitengo)
Dendrochronology imagwiritsa ntchito mapangidwe a mphete ya mitengo pachaka. Mitengo yomwe imamera m'dera linalake imawonetsa mawonekedwe a mphete yokhudzana ndi nyengo. Pogwirizanitsa mapangidwe a mphete ya zitsanzo za matabwa ofukula zakale ndi mndandanda wazinthu zofotokozera za madera, zaka za matabwa zimatha kudziwika ndi kulondola kwa pachaka, komanso nthawi zina ngakhale nyengo.
Njirayi ndi yamphamvu kwambiri ngati pali mndandanda wautali wazinthu zomwe zagwiritsidwa ntchito ndipo chitsanzo cha matabwa chili ndi mphete zokwanira. Dendrochronology imagwiranso ntchito yofunika kwambiri pakuwerengera ma radiocarbon, chifukwa mphete za mitengo zimapereka masiku a kalendala omwe angayerekezedwe ndi zotsatira za C-14.
Zoletsa: zimagwiritsidwa ntchito pa matabwa osungidwa bwino okha okhala ndi mzere womveka bwino wa mphete; si madera onse omwe ali ndi database yonse ya mphete ya mitengo.
3. Thermoluminescence (TL) ndi Optically Stimulated Luminescence (OSL)
Njira yowunikira imagwiritsidwa ntchito kudziwa nthawi yomwe mchere unayamba kuonekera pa kutentha kwambiri kapena kuwala.
– Thermoluminescence (TL) imagwiritsidwa ntchito kwambiri pa zinthu zadothi kapena miyala yomwe yatenthedwa (mwachitsanzo, panthawi yowotcha dothi). TL imayesa mphamvu "yotsekedwa" mu makristalo amchere; ikatenthedwa mu labotale, mphamvu iyi imatulutsidwa ngati kuwala. Imasonyeza nthawi kuyambira nthawi yowotcha komaliza.
– Kuwala Kolimbikitsidwa ndi Optically Stimulated Luminescence (OSL) nthawi zambiri kumagwiritsidwa ntchito poika mchenga kapena matope. OSL imayesa nthawi yomwe mchere unayamba kuonekera padzuwa lisanaikidwe m'manda.
Ubwino wa TL/OSL: ingagwiritsidwe ntchito pazinthu zomwe zilibe zinthu zachilengedwe; zothandiza pofufuza nthawi ya zinyalala ndi ntchito yoyaka. Zoletsa: zimafuna njira zosamala kwambiri zopezera zitsanzo kuti tipewe kukhudzana ndi kuwala (makamaka OSL), ndipo kutanthauzira kumadalira mbiri ya kukhudzana ndi chilengedwe.
4. Potaziyamu-Argon (K-Ar) ndi Argon-Argon (Ar-Ar)
Njira za K-Ar ndi Ar-Ar zimagwiritsidwa ntchito makamaka m'mikhalidwe yakale kwambiri komanso poyerekeza ndi zinthu za mapiri. Potaziyamu-40 imawola kukhala argon-40. Chifukwa argon ndi mpweya, imakhala "yotsekedwa" mu mchere wina pamene miyala ya mapiri ikuzizira. Poyesa chiŵerengero cha potaziyamu ndi argon, zaka za thanthwe zimatha kudziwika.
Njira imeneyi ndi yofunika kwambiri m'malo akale kwambiri, makamaka omwe akukhudzana ndi kusintha kwa anthu , chifukwa imatha kukhala ndi phulusa la mapiri lomwe limazungulira zinthu zakale kapena zinthu zakale.
Ubwino: yoyenera nthawi yayitali kwambiri (zaka mazana ambiri mpaka mamiliyoni ambiri). Zoyipa: sizigwira ntchito kumalo opanda mapiri ophulika; ndizofunika kwambiri pa geochronology kuposa zinthu zakale za tsiku ndi tsiku.
5. Uranium-Series (U-Series)
Kufufuza za Uranium-series kumagwiritsa ntchito kuwonongeka kwa uranium kulowa mu isotope yake ya mwana wamkazi (monga thorium). Njirayi ingagwiritsidwe ntchito pofufuza za calcite m'mapanga (stalagmites/stalactites), coral, ndipo nthawi zina mafupa kapena mano pansi pa mikhalidwe ina.
Mu kafukufuku wa zinthu zakale, mndandanda wa U nthawi zambiri umakhala wothandiza m'malo okhala ndi mapanga, mwachitsanzo kudziwa zaka za zigawo za calcite zomwe zimaphimba zojambula za m'mapanga kapena m'mbali mwa malo osungiramo zinthu zakale.
6. Archaeomagnetism ndi Paleomagnetism
Mphamvu ya maginito ya dziko lapansi imasintha pang'onopang'ono pakapita nthawi. Zipangizo zotenthetsera (monga ng'anjo, malo ophikira moto, kapena njerwa) zimatha "kulemba" njira ndi mphamvu ya mphamvu ya maginito pamene ikuzizira. Poyerekeza mbiri ya maginito iyi ndi ma curve a kusintha kwa geomagnetic m'madera osiyanasiyana, zaka za kuyaka zimatha kuyerekezeredwa.
Izi zimakhala zothandiza makamaka pamene malowa ali ndi zinthu zoyaka moto zomwe zidakalipo ndipo malowa ali ndi mawonekedwe abwino a geomagnetic reference curve.
Kuphatikiza njira: chronological triangulation
Akatswiri ofukula zinthu zakale nthawi zambiri samadalira njira imodzi. Kuti awonjezere kudalirika, amaphatikiza njira zingapo, monga radiocarbon date kuchokera ku makala amoto, OSL date kuchokera ku dothi lophimba pansi, ndi dendrochronology kuchokera ku matabwa omangira. Ngati zotsatira zake zikugwirizana, chidaliro pa nthawi yake chimawonjezeka. Ngati zikutsutsana, zimasonyeza vuto: kuipitsidwa kwa zitsanzo, kusakaniza zigawo, "zotsatira zakale za matabwa," kapena zochitika zosokoneza pambuyo pa kuchotsedwa kwa zinthu.
Kuphatikiza apo, njira zowerengera monga ku Bayesian modeling nthawi zambiri zimagwiritsidwa ntchito kuphatikiza deta yowerengera zaka ndi chidziwitso cha stratigraphic (kutsatana kwa zigawo). Izi zimathandiza kuti nthawi ichepe ndikupangidwa moyenera mkati mwa malo ofukula.
Mavuto omwe amapezeka nthawi zambiri pa chibwenzi chenicheni
Mavuto ena omwe nthawi zambiri amabuka ndi awa:
- Kuipitsidwa: zipangizo zamakono zimalowa mu zitsanzo zakale (kapena mosiyana), kusintha zotsatira zake.
- Vuto la kuyimira: chomwe chili ndi nthawi yake ndi "zinthu," osati nthawi zonse "chochitika" chomwe tikufuna kudziwa. Chitsanzo chabwino: matabwa ochokera ku mtengo wakale amatha kupereka zaka zakale kuposa nthawi yomwe adamangidwa.
– Zofooka za zinthu: si malo onse omwe ali ndi zotsalira zachilengedwe, matabwa osungidwa, kapena zinthu zophulika.
– Nkhani yosokonezeka: zochita za nyama, mizu, kufukulanso, kapena kusefukira kwa madzi kumatha kusuntha zinthu zakale kuchokera pamalo ake oyambirira.
Kutseka
Kudziwa tsiku lenileni ndi maziko ofunikira kwambiri a zinthu zakale zamakono chifukwa zimathandiza kuti pakhale kumangidwanso kwa nthawi ndi kuyesedwa kwa zakale. Pogwiritsa ntchito njira zosiyanasiyana—kuzindikira tsiku la radiocarbon, dendrochronology, luminescence, kudziwa tsiku la K-Ar/Ar, kudziwa tsiku la U-series, ndi archaeomagnetism—akatswiri ofufuza zinthu zakale amatha kuwerengera zaka za zinthu zomwe zapezeka kuyambira mazana mpaka mamiliyoni a zaka. Komabe, “kuzindikira tsiku lenileni” sikutanthauza popanda kusatsimikizika. Mphamvu ya njira imeneyi ili mu miyeso yake yowonekera bwino komanso yobwerezabwereza yasayansi, yomwe nthawi zonse imawerengedwa motsatira njira yowunikira ndi umboni wina. Kudzera mu kuphatikiza njira ndi kuwunika kozama kwa zitsanzo, kudziwa tsiku lenileni kumatithandiza kumvetsetsa nthawi komanso momwe anthu adapangira chikhalidwe, ukadaulo, ndi malo omwe timalandira lero.
