Maitiro ekutevera mavambo ezvigadzirwa zvechinyakare uchishandisa isotopes
Kutsvaga kwakabva chinhu—kwakabva zvinhu zvacho, kwazvakagadzirwa, uye kunyange nzira dzacho dzekutengeserana—ndichimwe chezvinetso zvikuru muzvidzidzo zvekuchera matongo netsika. Kwemakore, vaongorori vanga vachivimba nehunyanzvi, matekiniki ekugadzira, uye mamiriro ezvinhu ezvakawanikwa kuti vawane "nyaya" iri shure kwezvinhu zvekare. Zvisinei, nzira iyi dzimwe nguva inogona kuita kuti zviome kusiyanisa pakati pepesvedzero yetsika nekwakabva chinhu chacho. Apa ndipo panowanikwa ongororo yeisotope: isotopes inogona kushanda se "zvigunwe" zve geochemical zviri muchinhu chacho, zvichibatsira kuratidza zviratidzo zvekwakabva chinhu chacho neunyanzvi husingawanzoitiki nenzira dzinoonekwa chete.
Chii chinonzi isotopes uye nei zvichibatsira?
Isotopes imhando dzakasiyana dzemakemikari akafanana (nhamba imwe chete yemapurotoni) asi ine nhamba dzakasiyana dzemanyutron, zvichikonzera huwandu hwakasiyana. Semuenzaniso, kabhoni ine isotopes ^12C uye ^13C, okisijeni ine ^16O uye ^18O, uye strontium ine ^87Sr uye ^86Sr. Kusiyana uku kunogona kuita sekudiki, asi zvakasikwa zvinogadzira kusiyana kunoyerwa muzvikamu zve isotope mumatombo akasiyana, ivhu, mvura, uye kunyange zvipenyu. Nekuti zvigadzirwa zvinogadzirwa nezvinhu zvakatangira munzvimbo dzakatarwa, zviyero zve isotope muzvigadzirwa zvinowanzo chengeta ruzivo nezvenzvimbo dzazvo dzakatangira.
Chinhu chikuru chinobatsira ma isotopes ndechekuti akasimba. Ma isotope ratios mazhinji haachinje zvakanyanya mushure mekunge chinhu chacho chagadzirwa kana mushure mekunge chinhu chagadzirwa, kunyanya kana sampuro yacho yabatwa nemazvo uye kusvibiswa kwacho kuchidzorwa. Nekuenzanisa chiyero che isotope chechinhu ichi ne "isoscape" kana geological reference database, vaongorori vanogona kuona kana chinhu chacho chakabva munzvimbo A, B, kana C—kazhinji zvichidzika kusvika kunzvimbo chaiyo ye geological basin kana kwakabva mugodhi.
Nheyo huru: isotope "fingerprints" uye kuenzanisa kwavo
Kuongorora kweIsotope kunoshanda zvakanyanya kana paine zvinhu zviviri zviripo: (1) chinhu chinochengetedza chiratidzo cheisotopic, uye (2) data rekuenzanisa kubva kune zvinogona kuwanikwa. Kana chinhu chebronze chikafungidzirwa kuti chinoshandisa mhangura kubva kumigodhi yakasiyana-siyana, vaongorori vanofanirwa kuyera isotopes muchinhu chacho uye muore/slag/metal samples kubva kumigodhi iyoyo. Kuenderana mu isotope ratios kunogona kusimbisa fungidziro nezvekwakabva chinhu chacho.
Zvakakosha kuziva, zvisinei, kuti "kufananidza" hazvirevi nguva dzose kuti "chokwadi." Dzimwe nguva nzvimbo mbiri dzine zviyero zvakafanana zve isotope, kana kuti zvinhu zvinogona kunge zvakasanganiswa kubva kunzvimbo dzakasiyana-siyana. Nokudaro, isotopes dzinowanzobatanidzwa nekuongorora zvinhu zvishoma, zvidzidzo zvesimbi, petrography, kana ruzivo rwezvakacherwa kare zvakaita semamiriro ezvinhu enzvimbo.
Rudzi rwakajairika rwe isotope runoshandiswa kutsvaga mavambo ezvigadzirwa
1) Strontium isotopes (^87Sr/^86Sr): ma "geological tracers" anozivikanwa
Strontium inobatsira nekuti chiyero che ^87Sr/^86Sr chinosiyana zvichienderana nezera uye rudzi rwedombo. BatuaMatombo ekare, ane rubidium yakawanda anowanzova ne ^87Sr yakakwira nekuda kwekuora kwe ^87Rb. Strontium inopinda muvhu nemvura, yozopinda mumiti nemhuka, uye inozopedzisira yanyorwa mumazino, mapfupa, kana zvimwe zvinhu zvakasikwa.
Mukushandiswa kwezvinhu zvakagadzirwa, strontium inowanzoshandiswa pa:
– Kuziva kwakabva munhu (semuenzaniso pane enamel yemazino evanhu kuti zviongororwe kufamba kwemazino), izvo zvakakosha kana chinhu chacho chiri chemhuka kana kuti chine chekuita nekuvigwa.
- Kutsvaga zvinhu zvakagadziriswa zvinoenderana nemamiriro ekunze emuno, semuenzaniso lime, zvinhu zvekuvaka, kana zvinhu zvinotora Sr kubva mumvura.
Simba reSr riri padyo ne "signature" yejeologi, asi rinoda mamepu akanaka ekuenzanisa uye rinoda kutsanangura shanduko inogona kuitika mushure mekuiswa kwezvimwe zvinhu.
2) Masotopu emutobvu (Pb): kiyi yesimbi nematombo
Ma isotopes e lead akadai se ^206Pb, ^207Pb, ^208Pb (zvigadzirwa zvekuora zve uranium ne thorium) zvine ruzivo rwakawanda pakudzidza nezve simbi. Migodhi yakasiyana inogona kuva nePb ratios dzakasiyana, zvichiita kuti zvikwanisike kuteverwa kwezvinhu zvesimbi zvine lead (kana kusvibiswa kwePb kubva mu simbi). Nzira iyi inoshandiswa zvakanyanya kune:
- Kubatanidza zvinhu zvebronze, tin, sirivha, kana lead nenzvimbo dzakatarwa dzekuchera migodhi.
- Kunzwisisa network dzekutengeserana kwesimbi munguva dzekare uye yekare.
Dambudziko guru: maitiro ekunyungudutsa nekusanganisa simbi kubva kunzvimbo dzakasiyana anogona kugadzira "musanganiswa" wema isotopes anovhara mavambo mamwe chete. Nokudaro, ongororo inowanzo batanidzwa ne trace element uye mamiriro e metallurgical.
3) Okisijeni (δ^18O) uye hydrogen (δD) isotopes: tsoka dzemvura nemamiriro ekunze
Okisijeni nehydrogen zvinoshandiswa zvakanyanya kuronda hukama huripo pakati pemvura nemamiriro ekunze. Mune zvimwe zvinhu—zvakaita secarbonates, mapfupa, mazino, kana kunyange magirazi neceramics mune dzimwe nguva—zvikamu zveisotope zvinogona kunyora kuumbwa kwemvura kana tembiricha yemunzvimbo.
Kune zvinhu zvakagadzirwa, δ^18O inogona kubatsira:
– Ongorora kana chinhu (semuenzaniso goko, kabhoni) chakagadzirwa munzvimbo yegungwa kana yepasi kana munzvimbo yemamiriro ekunze akati.
- Inotsigira pfungwa yekuti zvinhu zvakabva papi kana ikabatanidzwa neSr kana mamwe mashoko.
Zvisinei, dudziro yeδ^18O inowanzo kuve yakaoma nekuti inokonzerwa nemwaka, kukwirira, daro kubva kumahombekombe, uye maitiro ekupisa panguva yekugadzirwa.
4) Isotopes dzekabhoni (δ^13C) nenitrogen (δ^15N): mamiriro ehupenyu uye manyuko ezvisikwa
Ma isotopu eC neN anowanzo shandiswa kutsvaga zvinhu zvakasikwa: chikafu, mhando yemiti (C3 vs. C4), kana kuti kwakabva zvinhu zvakaita semachira, bepa, resin, uye zvasara zvechikafu pahari. Mukutsvaga zvinhu zvekare:
– Zvisaririra zvekudya zviri muhari zvinogona kuongororwa kuti zvionekwe kana zvakanyanya kubva mugungwa kana kuti panyika.
– Matayi ejira anogona kupa zviratidzo nezvenzvimbo inokura zvirimwa (semuenzaniso, flax, donje) kana paine ruzivo rwekuenzanisa.
Idzi isotopes dzine simba guru pakutsanangura zvakatipoteredza nemaitiro ehupenyu, uye dzinozobatanidzwa nekwakabva kuburikidza nekutsigira ruzivo rwenzvimbo.
Maitiro ekutevera anoitwa sei?
1) Sarudza mibvunzo yekutsvagisa
Kuongorora kweIsotope kunofanira kutanga nemubvunzo wakajeka: unoda kutsvaga mugodhi wesimbi here, kwakabva ivhu receramic, kwakabva dombo, kana kufamba kwevanhu vane chekuita nechinhu chakagadzirwa? Mubvunzo wega wega unoda isotopes dzakasiyana uye nzira dzekutora sampuli. Semuenzaniso, Pb inonyanya kukosha kune simbi, nepo Sr neO mu enamel yemazino zvakanyanya kufambiswa kwevanhu.
2) Kutora sampuli kusingakuvadzi zvakanyanya
Nekuti zvinhu izvi zvinokosha uye zvakachengetedzwa, kutora sampuli kunoitwa nekungwarira kukuru: uchishandisa machipisi madiki, kucherwa kwemicro-drilling, kana kukwesha zvakasara. Maitiro ekuchengetedza akakosha kudzivirira kukuvara kwemaziso uye kwemaumbirwo. Uyezve, vaongorori vanofanirwa kuve nechokwadi chekuti sampuli hadzina kusvibiswa nezvinhu zvemazuva ano zvekuchengetedza (glues, coatings) zvinogona kuchinja kuumbwa kwemakemikari.
3) Kugadzirira uye kuyerwa kwemurabhoritari
Mienzaniso inowanzo chenurwa, kunyungudutswa (kune dzimwe simbi/zvicherwa), uye ma isotope avo anoyerwa uchishandisa chishandiso chakadai se mass spectrometer (semuenzaniso, TIMS kana MC-ICP-MS). Zvishandiso izvi zvinokwanisa kuyera mutsauko muzvikamu zve isotope nemazvo. Rabhoritari inoshandisawo zviyero zvepasi rose uye maburi kuti ive nechokwadi chekuti mhinduro dzakavimbika.
4) Enzanisa nedhatabhesi uye modhi
Makoshero e isotopic ezvigadzirwa zvakazoenzaniswa ne:
- Ruzivo rwekuchera/matombo munharaunda,
- Mamepu enzvimbo dze isoscape,
- Zviunganidzwa zvemareferensi emiziyamu kana mhedzisiro yekutsvagisa yapfuura.
Kazhinji, mhedzisiro yacho haingoratidzi nzvimbo imwe chete, asi kuti "nzvimbo yemikana" inopfupikiswa neruzivo rwakawanda - senge maitiro ekushongedza, tekinoroji yekugadzira, kana kugoverwa kwekutengeserana kunozivikanwa.
5) Dudziro mune zvekuchera matongo
Danho rakakosha nderekuisa nhamba dze isotope munyaya yezvekuchera matongo. Semuenzaniso, kana isotope yePb ichiratidza simbi kubva kunzvimbo iri kure yekuchera migodhi, nepo maitiro echinhu chacho ari emunharaunda, saka pane chiratidzo chezvinhu zvakatorwa kunze kwenyika asi kugadzirwa kwenzvimbo. Kusiyana neizvi, kana zvinhu zvacho nemaitiro acho zvese zvichiratidza, chinhu chacho chingangove chinhu chakakosha chose.
Zvipingamupinyi uye yambiro
Kuongorora kweIsotope hakusi "GPS yekare." Pane zvipingamupinyi zvakakosha:
- Kusanganisa simbi: simbi dzinowanzo shandiswazve kana kusanganiswa, zvichikonzera chiratidzo chakasanganiswa.
– Kusvibiswa uye kushandurwa: kuvigwa kwenguva refu kunogona kuchinja pamusoro pechinhu chacho; saka kusarudzwa kwechikamu chemuenzaniso kwakakosha zvikuru.
- Kuwanikwa kwedata rekuenzanisa: pasina dhatabhesi renzvimbo, dudziro inova yekufungidzira.
- Kufanana kwenzvimbo pakati penzvimbo: nzvimbo mbiri dzakasiyana dzinogona kuva nezvikamu zvakafanana zve isotope, saka data re multi-isotope kana mamwe ma data anodiwa.
Saka, nzira yakanakisisa ndeyekushandisa zviratidzo zvakawanda: semuenzaniso kusanganisa Pb isotopes nezvinhu zvidiki zvesimbi, kana Sr + O kuti zviongororwe kufamba, uye kugara uchibatanidza mhedzisiro neuchapupu hwezvakacherwa mumatongo.
Mhedziso: isotopes semakiyi enetwork dzekare
Nekuongorora isotope, zvinhu zvakagadzirwa nemaoko hazvisisiri zvinhu zvisina upenyu chete, asi zviri mumatura emakemikari ane ruzivo nezvenzvimbo, migodhi, kurima, uye kufamba kwevanhu. Nzira iyi yakabatsira kuwana nzira dzekare dzekutengeserana nesimbi, kufamba kwevanhu, uye manyuko ezvinhu zvekuvaka zvikuru. Kunyange zvazvo isiri isina miganho yayo, nzira yeisotope—kunyanya kana ikabatanidzwa nedzimwe nzira dzesainzi nezvidzidzo zvekuchera matongo—inopa nzira yakanyatsojeka yekutsvaga mavambo ezvinhu zvakagadzirwa nemaoko uye kuvakazve mambure ehukama pakati pevanhu vekare.
