Cyclostratigraphy

Cyclostratigraphy wani bangare ne na stratigraphy wanda ke nazarin yanayin yanayi na tilasta a cikin jerin abubuwan da suka faru.

 Canje-canje na sararin samaniya 
Tsarin taurari (wanda aka fi sani da Milankovitch cycles) bambance-bambance ne na yanayin duniya a kusa da Rana saboda hulɗar nauyi tare da wasu taro a cikin Tsarin Hasken rana.[1] Saboda wannan cyclicity, hasken rana ya bambanta ta hanyar lokaci a kan bangarori daban-daban kuma yanayin yanayi yana shafar. Wadannan bambance-bambance na insolation suna da tasiri a kan yanayin duniya da kuma a kan zubar da duwatsu.￼

Babban zagaye na orbital shine precession tare da manyan lokutan 19 da 23 kyr, obliquity tare da manyan lokuta na 41 kyr, da 1.2 Myr, da eccentricity tare da babban lokutan kusan 100 kyr, 405 kyr, da 2.4 Myr.  Precession yana tasiri ga yawan insolation da kowane hemisphere ke karɓa. Obliquity yana sarrafa tsananin yanayi. Abinda ke da alaƙa yana rinjayar yawan insolation da Duniya ke karɓa gaba ɗaya. Bambancin hasken rana kai tsaye yana tasiri ga yanayin duniya, kuma canje-canje a cikin hazo da yanayin yanayi an bayyana su a cikin rikodin sedimentary. Tsarin 405 kyr eccentricity yana taimakawa wajen gyara jerin lokuta a cikin duwatsu ko ƙwayoyin sedimentation lokacin da canji mai canzawa ya sa su da wuya a sanya su. Masu nuna alamun waɗannan sake zagayowar a cikin turɓaya sun haɗa da magnetism na dutse, geochemistry, abun da ke cikin halittu, da siffofin jiki kamar launi da canje-canje.

 Hanyoyin Dating da aikace-aikace 
Don ƙayyade lokacin binciken cyclostratigraphic, ana tsara duwatsu ta amfani da kwanan wata na radiometric da sauran hanyoyin stratigraphic. Da zarar an daidaita lokacin, ana bincika duwatsu don siginar Milankovitch. Daga can, ana iya sanya shekaru zuwa yadudduka masu laushi bisa ga siginar astronomical da suke ƙunshe da su.

Nazarin cyclostratigraphic na rubuce-rubucen dutse na iya haifar da daidaitattun kwanan wata na abubuwan da suka faru a cikin ilimin ƙasa da suka gabata, don haɓaka fahimtar dalilin da sakamakon Tarihin Duniya (yanayi) , da kuma fahimtar mafi kyawun sarrafawa akan hanyoyin da aka ajiye na sediments da halayyar tsarin sedimentary. Cyclostratigraphy kuma yana taimakawa nazarin kimiyyar lissafi na duniya, saboda yana ba da bayani game da sake zagayowar taurari wanda ya wuce 50 Ma (model na taurari ba daidai ba ne bayan wannan).  Za'a iya amfani da kewayon lokaci ga waɗannan zagayen taurari don daidaita 40Ar / 39Ar dating.

 Ƙuntatawa 
Har ila yau, rashin tabbas yana tasowa yayin amfani da cyclostratigraphy. Yin amfani da kwanan wata na radioisotope don saita sigogi don ma'auni na lokaci yana gabatar da matakin rashin tabbas. Har ila yau, akwai rashin tabbas na stratigraphic, rashin tabbas saboda tilasta yanayi, da rashin tabbas game da tasirin juyawa na Duniya akan precession. Har ila yau, akwai rashin tabbas a cikin bayanan da suka wuce 50 Ma saboda samfuran astronomical ba daidai ba ne fiye da 50 Ma saboda rikici da rashin tabbas na yanayin farko.

 Dubi kuma 

 Rashin ruwa na cyclic
 Tsarin Milankovitch
 Rubuce-rubuce

 Manazarta