Nyika yedu yakapidiguka makore 84 miriyoni apfuura apo ma<em>dinosaur akafamba panyika. Kunyanya, chiitiko chinonzi real pole shift chinoitika, chinokwanisa kushandura kurerekera kwemuviri wekudenga maererano neaxis yayo uye kukonzera "kuzununguka". Pane zvimwe zvidzidzo zvinotsigira izvozvo nyika inogona kupenengura paasisi yayo uye izvi zvinogona kukonzera matambudziko akakomba kuvanhu nehupenyu sezvatinozviziva.
Nechikonzero ichi, isu tichakumikidza chinyorwa ichi kukuudza kuti Nyika inogona sei kutenderedza axis yayo uye kuti ndezvipi mhedzisiro yainogona kuve nayo.
Nyika inogona kupenengura paaxis yayo
Kuchinja kwepariro kwechokwadi kunoitika kana mapango ePasi ari kuchamhembe nekumaodzanyemba achinja zvakanyanya, zvichiita kuti goko rakasimba ripinde mumvura yekumusoro yejasi inodzivirira musimboti. Hapana magineti kana hupenyu paPasi hwakakanganiswa, asi dombo rakadzingwa rakanyora kukanganisa nenzira yepaleomagnetic data.
“Fungidzira uri kutarisa Pasi uri muchadenga,” anotsanangura kudaro Joe Kirschvink, nyanzvi yezvepasi paTokyo Institute of Technology muJapan, uye mumwe wevanyori. "Chokwadi polar drift inopa fungidziro yekuti pasi rinorerekera kune rimwe divi, kana chiri kunyatsoitika ndechekuti nzvimbo ine dombo (yakasimba mantle uye crust) inotenderera pamusoro peiyo jasi remvura uye ichitenderedza kunze mukati" .
"Matombo mazhinji akarekodha kutariswa kwenzvimbo yemagineti sezvavakagadzira, zvakafanana nematepi anorekodha mimhanzi," iyo Institute yakatsanangura mune chirevo. Semuenzaniso, madiki magineti makristasi anoumba magnetosomes anobatsira mabhakitiriya akasiyana kuti azvitungamirire uye aenderane nemagineti matanda. Sezvo matombo akasimba, vakabatwa uye vakagadzira "microscopic compass tsono," zvichiratidza paive nedanda uye kuti raifamba sei munguva yekupedzisira yeCretaceous.
Uyezve, chinyorwa ichi chemagnetic field chinoita kuti tizive kuti dombo riri kure zvakadini kubva kumucheto: muNorthern hemisphere, kana yakanyatsomira, zvinoreva kuti iri padanda, nepo kana yakachinjika, inoisa kuequator. Shanduko yekutarisa kwezvikamu zvinoenderana nenguva imwechete ingaratidza kuti nyika "inozununguka" paaxis yayo.
Zvidzidzo zvekuti Nyika inogona kupenengura paaxis yayo
Kuti awane zviratidzo zvechiitiko ichi, mumwe munyori, Purofesa Ross Mitchell weInstitute of Geology and Geophysics muBeijing, China, akayeuka nzvimbo yakakwana yaakaongorora somudzidzi. Iri iLake Apiro, mumakomo eApennine, pakati peItaly, pakaumbwa dombo reraimu panguva yavaifarira kuongorora: pakati pemakore 1 kusvika 65,5 miriyoni apfuura, zuva rekufungidzira rekutsakatika kwemadinosaur.
Inotungamirwa neiyo yechokwadi polar wander hypothesis, data yakaunganidzwa paLimestone yekuItaly inoratidza kuti Nyika yakarereka ingangoita gumi nemaviri madhigirii isati yazvigadzirisa. Mushure mekurereka, kana "kupeta", pasi redu rakachinja nzira uye pakupedzisira rakadhirowa arc inoda kusvika 12 °, iyo inotsanangurwa nevanyori se "full offset" uye "cosmic yo-yo" inotora makore angangoita mamiriyoni mashanu.
Tsvagiridzo yapfuura yakaramba mukana weiyo yechokwadi polar kudzungaira pakupera kweCretaceous nguva, kubheja pakugadzikana kweakisi yePasi mukati memakore zana apfuura emamiriyoni. "pasina kuunganidza data rakakwana kubva kune geological rekodhi," vanyori vepepa vakadaro. "Ndicho chimwe chezvikonzero nei chidzidzo ichi uye hupfumi hwayo hwepaleomagnetic data inozorodza," nyanzvi yefizikisi Richard Gordon weRice University muHouston akawedzera mumashoko.
Tsanangudzo yesainzi
Nyika idenderedzwa rine mativi ane simbi yakasimba mukati mepakati, simbi yekunze core, uye mantle akasimba uye crust inotonga pamusoro penzvimbo yatinogara. Vese vanotenderera sepamusoro, kamwe chete pazuva. Nokuti Nheyo yekunze yepasi imvura, jira rakasimba uye goko rinogona kutsvedza pamusoro paro. Zvimiro zvakakora, sekudzikisa mahwendefa emunyanza uye makomo makuru anoputika seHawaii, anofarira kuva pedyo neequator.
Kunyangwe ichi crustal displacement, Nyika yemagineti inogadzirwa nemafashama mu convective liquid simbi Ni-Fe mune yekunze musimboti. Pazvikero zvenguva refu, kufamba kwejasi rakafukidzira uye crust hakukanganise pakadzika pePasi, nekuti iwo matombo akaturikidzana aya anoonekera kune Earth magnetic field. Panzvimbo iyoyo, maconvection mapatani mune iyi yekunze musimboti anomanikidzwa kutamba achitenderedza axis yePasi yekutenderera, zvichireva kuti iyo general pateni yePasi remagineti inotarisika, achipararira nenzira imwechete iyo mafirita esimbi anomira pamatanda madiki magineti.
Saka iyo data inopa ruzivo rwakanakisa nezve geographic yakatarisa kuchamhembe nekumaodzanyemba pole, uye kurereka kunopa chinhambwe kubva pamatanda (wakamira munda zvinoreva kuti uri pamatanda, yakachinjika munda zvinoreva kuti uri kuequator). Matombo mazhinji anorekodha nzira yenzvimbo yemagineti yenzvimbo sezvaanoumba, senge tepi rekodhi mimhanzi. Semuenzaniso, makristasi madiki emamineral magnetite anogadzirwa nemamwe mabhakitiriya anonyatso kukwira senge tsono diki dzekambasi uye dzinobatwa mumatope sezvo dombo rinosimba. Iyi "fossil" magineti inogona kushandiswa kuronda kuti axis yekutenderera yafamba papi zvichienderana nepasi.
"Fungidzira uchitarisa Pasi kubva muchadenga," anotsanangura kudaro munyori wekudzidza Joe Kirschwenk weTokyo Institute of Technology, uko ELSI yakavakirwa. "Chokwadi polar drift inoita kunge Nyika iri kurerekera kune rimwe divi, kana chiri kunyatsoitika idombo rese rekunze goko rePasi (solid mantle and crust) richitenderera mukati memvura yekunze." Yechokwadi polar Drift yakaitika, asi Nyanzvi dzeGeologist dzinoramba dzichikakavadzana kana kutenderera kukuru kwejasi rePasi uye goko kwakaitika munguva yakapfuura.
Ndinovimba kuti neruzivo urwu unogona kudzidza zvakawanda nezve Nyika inogona kubatidza axis yayo.