Maitiro eMagetsi eRekodha Mapuratifomu eRekodha
Funga nezvepasi pegungwa se "archive" hombe inochengetedza zviratidzo zvenguva. Kwete muchimiro chakanyorwa, asi mumapatani emagineti ari mumatombo. Mapatani aya—mitsara yemagineti yakafanana pasi pegungwa—ave humwe hwehumbowo hwakasimba hwekuti maplate e tectonic anofamba zvechokwadi. Kuburikidza nezvinyorwa izvi zvemagineti, masayendisiti anogona kuona kuti goko regungwa rakaumbwa riini, kuti pasi pegungwa rakapararira nekukurumidza sei, uye kuti maplate ePasi akachinja sei kwemamiriyoni emakore.
Magnetism yePasi uye "Compass" Yechisikigo muMatombo
Nyika ine simba remagineti repasi rose rakafanana negiant bar magnet. Mitsetse yesimba remagineti inobuda pedyo negomo rekumaodzanyemba remagineti yopinda pedyo negomo rekumaodzanyemba remagineti. Simba iri remagineti harina kugadzikana: simba raro rinogona kuchinja, nzvimbo dzematanda emagineti dzinogona kuchinja, uye chinonyanya kukosha pakukurukurirana uku—dzimwe nguva rinodzosera divi kumashure (geomagnetic reversal). Kana kutendeuka kukaitika, divi resimba remagineti rePasi rinochinja madhigirii zana nemakumi masere: kambasi yainongedza "kuchamhembe" ikozvino inongedza "kumaodzanyemba" (mupfungwa yemagnetic).
Saka izvi zvinei nematombo? Matombo mazhinji, kunyanya ayo anobva ku magma, ane zvicherwa zvemagineti zvakaita semagnetite (Fe₃O₄). Kana magma yatonhora yoshanduka kuita dombo reigneous, zvicherwa zvemagineti zviri mairi "zvinovhara" gwara remunda wemagineti wePasi kana yaoma. Maitiro aya anonzi remanent magnetization. Nemamwe mashoko, matombo eigneous akaumbwa panguva yakatarwa anogona kushanda sedata loggers: kuchengetedza gwara remunda wemagineti wePasi panguva yavakazvarwa.
Mid-Ocean Ridge: Fekitori Itsva yeGoko
Chinhu chikuru chinoita kuti plate irambe ichifambiswa nemagineti igomo riri pakati pegungwa. Iri igomo rakatevedzana riri pasi pemvura rinoumbwa pamiganhu yeplate dzakasiyana, uko plate mbiri dzinofamba dzakaparadzana. Sezvo plate dzichifamba dzakaparadzana, magma inobva muganda inokwira kuti izadze mukaha, yozosimba kuita goko idzva regungwa. Maitiro aya anoenderera mberi anonzi kupararira kwepasi pegungwa.
Nekuti goko idzva rinogara richiumbwa pakati pegungwa, pasi pegungwa pacho panoita sebhandi rekufambisa: goko diki riri pakati chaipo (pagomo), rozokura parinoenda kuruboshwe nekurudyi. "Chikamu" chimwe nechimwe chegoko chinoumbwa panguva yakatarwa chinonyora divi resimba remagineti rePasi panguva iyoyo. Kana simba remagineti riri renguva dzose munguva iyoyo, matombo achaiswa magineti nenzira yakajairika; kana iri nguva yekudzokera shure, matombo achaiswa magineti nenzira yakatarisana.
Mitsetse yeMagineti Yakaenzana: Zviratidzo zveManotsi zveKuwedzera
Masayendisiti paakaongorora magadzirirwo emagnetic anomalies pasi pegungwa achishandisa mamagnetometers akadhonzwa, akawana patani inoshamisa: mabhandi emagnetic anomalies anomhanya akaenzana nemakomo epakati pegungwa uye akarongwa zvakaenzana kumativi ese. Mabhandi aya aichinjana pakati pe "zvakajairika" uye "zvakadzoserwa".
Sei patani yekusunga ichiita izvi? Nekuti goko regungwa rinoramba richiumbwa, nepo simba remagineti rePasi dzimwe nguva riri renguva dzose uye dzimwe nguva richidzokera shure. Fungidzira mitsetse yekupenda pabhandi rekufambisa: kana pendi nhema yaiswa, rimwe band rinoumbwa; kana pendi chena yaiswa, rimwe band rinoumbwa; zvichingodaro. Pasi pegungwa, "pendi" iyoyo ndiyo polarity yesimba remagineti. Kana magma yaoma pakati pegungwa, inonyora polarity yemazuva ano, yozotakurwa sezvo maplates achifamba. Nekuti kupararira kunoitika kumativi ese ari maviri nekuenzanisa, patani imwechete yekusunga inoonekwa kumativi ese egomba—zvichigadzira symmetry yakasiyana zvikuru.
Maitiro aya akafanana humbowo hwakasimba hwekuti pasi pegungwa riri kufamba uye richivandudzwa nguva dzose. Inopindurawo mubvunzo wekare wekuti: goko rekare regungwa rinoenda kupi? Mhinduro: rinozopedzisira radzikiswa pasi pemamwe maplate panzvimbo dzinoshandiswa, rozodzoserwa mugomba.
Karenda yeMagineti: Kushandura Mapatani Kuita Nguva
Mapatani emagineti haangoratidzi chete kuti mapuratifomu ari kufamba, asiwo anobvumira kunyorwa kwenguva. Masayendisiti akagadzira nguva yegeomagnetic polarity zvichibva padata kubva ku lava yepasi rose inogona kunyorwa nguva uchishandisa nzira dze radiometric (semuenzaniso, potassium-argon kana argon-argon). Chiyero ichi chinonyora nguva dzese dze polarity yakajairika uye yakadzoserwa shure mumakore miriyoni apfuura.
Kana mapatani emagineti ari pasi pegungwa akaenzaniswa nenguva inodzokororwa pasi rose, bhendi rega rega rinogona "kuenzaniswa" nenguva yakatarwa. Zvakafanana nekufananidza barcode: kutevedzana kwakafanana kwemabhendi kunoratidza kutevedzana kwenguva imwe chete. Saka, masayendisiti anogona kuona zera regomba regungwa panzvimbo chaiyo kubva pamaitiro aro emagineti.
Kuyera Kumhanya kwePlate Shift
Kana ganda rava kuzivikanwa kuti zera reganda racho nderei, danho rinotevera nderekuyera kuti ndiro dziri kufamba nekukurumidza zvakadii. Nzira yacho iri nyore kunzwisisa:
1. Yera daro retepi yemagineti kubva pamucheto wegomba repakati pegungwa (uko goko rinoumbwa).
2. Sarudza zera retepi kubva pachikero chemagnetic reversal.
3. Kukurumidza kuwedzera = daro / nguva.
Semuenzaniso, kana bhendi rakaumbwa makore mamiriyoni mashanu apfuura riri makiromita zana kubva pagomo, saka mwero wekupararira kudivi rimwe i100 km / mamiriyoni mashanu emakore = 20 km pamamiriyoni emakore, kana 2 cm pagore. Nekuti kupararira kunoitika kumativi ese, mwero wekuparadzaniswa kwemaplate maviri unogona kupetwa kaviri (zvichienderana netsananguro yakashandiswa).
Vachishandisa nzira iyi, vaongorori vakaona kuti mwero wekufamba kweplate unosiyana: mimwe inongosvika mamirimita mashoma pagore, mimwe masendimita akati wandei pagore—zvichienzaniswa nemwero unokura nzara dzevanhu.
Kugadziriswazve kweKufamba kwePlate Munguva Yakapfuura
Mapatani emagineti anobatsirawo pakuvakazve nhoroondo yekuvhurwa kwegungwa uye kuyerera kwekondinendi. Atlantic payakatanga kuvhurwa, goko idzva regungwa rakaumbwa paMid-Atlantic Ridge. Mabhandi emagineti akachengetedzwa pasi peAtlantic ikozvino anonyora kuti Africa neAmerica zvakaparadzana sei zvishoma nezvishoma. Nekubatanidza makore emabhandi, nzvimbo yegomo, uye geometry yemaplate, masayendisiti anogona kudzokera shure "firimu" retectonic: vachifungidzira nzvimbo dzemakondinendi mamiriyoni emakore apfuura.
Pamusoro pezvo, shanduko mugwara remugomo kana kusarongeka kwemapatani emabhandi zvinogona kupa zviratidzo zvekuchinja kwemasimba etectonic, kuchinja kwekufamba kweplate, kana zviitiko zvakaita sekusvetuka kwemugomo. Saka, rekodhi yemagineti haisi yekumhanya chete, asiwo kuti mashandiro ehurongwa hwetectonic anochinja sei nekufamba kwenguva.
Sei Uchapupu Hwacho Hwakasimba Kwazvo?
Pamberi pekuwanikwa kwemagadzirirwo emagineti pasi pegungwa, pfungwa yekudonha kwemakondinendi (yakataurwa naAlfred Wegener) yakarambwa zvakanyanya nekuti pakanga pasina nzira kana humbowo hwakasimba hwekutsanangura kuti makondinendi aigona kufamba sei. Mamepu emitsara yemagineti akafanana akapa humbowo hwehuwandu uye hwepasi rose: maitiro akafanana akawanikwa mumakungwa mazhinji, zvichienderana nekudzoserwa kwesimba remagineti rePasi zvakare rakanyorwawo mumatombo epasi, uye zvinoenderana nepfungwa yekuti goko idzva rinozvarwa pakati pegungwa uye rarasika munzvimbo dzinoshandiswa.
Uchapupu uhwu hunogona kuyerwawo. Haungooni chete kuti chimwe chinhu chinokodzera; unogona kuverenga zera racho uye mwero wekufamba kwaro. Izvi ndizvo zvakaita kuti paleomagnetism yepasi pegungwa ive chinhu chakakosha mukuzvarwa kwedzidziso yemazuva ano yeplate tectonics pakati pezana remakore rechi20.
Penutup
Mapatani emagineti ari pasi pegungwa inhoroondo yenhoroondo yePasi yakachengetwa mudombo. Bande rega rega remagineti anomalies rinonyora divi resimba remagineti sezvo goko rakaumbwa, uye nekuti goko regungwa rinobva pamakomo ari pakati pegungwa, mapatani acho akarongwa zvakanaka uye akaenzana. Nekuzvienzanisa nehukuru hwemagineti anodzoka, masayendisiti anogona kuona zera regoko, kuverenga mwero wekupararira, uye kugadzirazve kufamba kweplate kwemamiriyoni emakore. Kubva ku "mitsetse" iyi isingaoneki, tinoverenga kuchinja kwemaplate - humbowo hwekuti pamusoro pePasi sisitimu mhenyu, inofamba, uye inogara ichichinja.
Kana muchida, ndinogona kuwedzera mufananidzo wepfungwa yetepi yemagineti (dhayagiramu iri nyore), kana kugadzirisa chinyorwa ichi kuti chienderane nemaitiro anozivikanwa (akareruka) kana esainzi (ane hunyanzvi) sezvinodiwa.
