Momwe Zakale Zimathandizira mu Deta ya Stratigraphic
Kuphunzira mbiri ya Dziko Lapansi kuli ngati kugwiritsa ntchito buku lakale, lowonongeka komwe masamba nthawi zambiri amasowa kapena kusweka. Akatswiri a mbiri yakale ndi akatswiri a za nthaka, mofanana ndi akatswiri a mbiri yakale akhama, amayesetsa kukonzanso nkhaniyi kudzera m'njira zosiyanasiyana. Pakati pa izi, kugwiritsa ntchito zinthu zakale potanthauzira deta ya stratigraphic kumakhalabe njira yothandiza kwambiri komanso yothandiza kwambiri. Zinthu zakale zimapereka dongosolo lowerengera nthawi, zimavumbula momwe zinthu zilili m'chilengedwe, komanso zimathandiza kulumikiza zigawo zosiyanasiyana patali. Nkhaniyi ifufuza momwe zotsalira za moyo wakalezi zilili zofunika kwambiri pakuphunzira stratigraphy.
Zakale monga Zizindikiro za Biostratigraphic
Biostratigraphy ndi nthambi ya stratigraphy yomwe imayang'ana kwambiri pa mgwirizano ndi ubale wa zigawo za miyala kudzera mu zomwe zili m'mabwinja. Imadalira mfundo ya kuloŵana kwa zinyama, yomwe William Smith adaifotokoza kumayambiriro kwa zaka za m'ma 19. Smith adawona kuti zigawo za miyala ya sedimentary (strata) zinali ndi magulu osiyanasiyana a mafupa a nyama zakale ndipo magulu amenewa anatsatizana motsatizana. Mfundo imeneyi imathandiza akatswiri a za nthaka kugawa zaka za mitundu yosiyanasiyana ndi kuzigwirizanitsa m'madera osiyanasiyana.
Mwachitsanzo, ngati Gawo A ku South America lili ndi Zakale X zomwe zimapezekanso mu Gawo B ku Africa, munthu angaganize kuti zigawozi zili ndi zaka zofanana. Kugwirizana kotereku kwakhala kofunikira kwambiri popanga nthawi ya geology ndikumvetsetsa kufalikira kwa malo okhala ndi kontinenti ndi nyanja pakapita nthawi.
Zolemba Zakale
Chofunika kwambiri pa biostratigraphy ndi zinthu zakale zodziwika bwino. Izi ndi zinthu zakale zamoyo zomwe zili ndi malo ambiri koma nthawi yochepa. Kupezeka kwawo mkati mwa thanthwe sikungotanthauza zaka za thanthwe komanso kupezeka kwake m'madera osiyanasiyana. Ma Trilobite, ammonite, ndi ma foraminifera ena ndi zitsanzo zabwino kwambiri za zinthu zakale zodziwika bwino.
Mwachitsanzo, ammonite Dactylioceras, yomwe imapezeka kwambiri mu Jurassic strata, imagwiritsidwa ntchito ngati fossil yosonyeza zinthu zakale. Kupezeka kwake kumathandiza akatswiri a za nthaka kuzindikira miyala yakale ya Jurassic padziko lonse lapansi. Kulondola komwe kumaperekedwa ndi fossil yosonyeza zinthu zakale kumathandiza kuti mbiri ya Dziko Lapansi ikhale yolondola komanso yolondola.
Mabwinja ndi Kukonzanso Zachilengedwe
Zinthu zakale zomwe zinapezeka m'mabwinja a pansi pa nthaka sizimangosonyeza miyala yokha. Zimapereka mbiri ya malo akale, kupereka chidziwitso cha nyengo yakale, kuchuluka kwa nyanja, ndi momwe zinthu zinalili m'chilengedwe. Pophunzira za zinthu zakale zomwe zinapezeka m'mabwinja a pansi pa nthaka, akatswiri a za nthaka amatha kudziwa ngati gulu linalake la zinthu zakale linaimira malo a m'nyanja, nyanja yamadzi oyera, chipululu, kapena dera lokhala ndi nkhalango.
Zinthu zakale za m'nyanja monga ma coral ndi mitundu ina ya plankton zimasonyeza malo okhala m'nyanja, pomwe zinthu zakale za zomera ndi nsomba za m'madzi oyera zimasonyeza malo okhala m'nyanja kapena m'madzi oyera. Kuphatikiza apo, kupezeka kwa zinthu zakale zina kungasonyeze nyengo yakale; mwachitsanzo, kupezeka kwa masamba a kanjedza opangidwa ndi mafupa m'nthaka ya Arctic kukusonyeza kuti derali kale linali ndi kutentha kotentha kwambiri.
Paleontology ndi Sequence Stratigraphy
Sequence stratigraphy ndi njira yapamwamba yowunikira stratigraphic yomwe imagwirizanitsa sedimentology, stratigraphy, ndi paleontology. Imayang'ana kwambiri kumvetsetsa ma depositional sequences—ma consistency motsatizana a miyala ya sedimentary yomwe ili ndi kusagwirizana. Mafosholo osungiramo zinthu zakale amachita gawo lofunika kwambiri pano pothandiza kukhazikitsa nthawi ya ma sequences awa ndikumvetsetsa kusintha kwa malo osungiramo zinthu.
Mwachitsanzo, kuzindikira zamoyo zam'madzi zopanda mafupa zomwe zili pamwamba pa gawo lomwe lili ndi mafupa a zomera zapadziko lapansi kungasonyeze kuti pali malo ozungulira nyanja—kumene madzi a m'nyanja amakwera pamwamba pa nthaka yomwe inali itawonekera kale. Mosiyana ndi zimenezi, kupezeka kwa mafupa a padziko lapansi pamwamba pa nthaka ya m'nyanja kungasonyeze kuti madzi a m'nyanja akubwerera m'mbuyo, zomwe zimasonyeza kuchepa kwa madzi a m'nyanja.
Zolemba Zakale ndi Kuwerengera Nthawi
Chronostratigraphy, nthambi ya stratigraphy yokhudzana ndi ubale wa nthawi ndi zaka za miyala, imadalira kwambiri zinthu zakale. Popeza nthawi zambiri zimakhala zovuta kugwiritsa ntchito njira ya radiometric date pa miyala ya sedimentary (yomwe nthawi zambiri imakhala ndi mchere woyenera wa mtundu uwu wa deti), zinthu zakale zimapereka njira ina yofunika kwambiri. Mwa kuzindikira ndi kupeza madeti a phulusa la volcano mkati mwa sedimentary sequences (popeza izi zitha kuwerengedwa ndi deti ya radiometric), ndikuzigwirizanitsa ndi zinthu zakale, akatswiri a za nthaka amatha kupanga njira yolondola kwambiri ya chronostratigraphic.
Njira imeneyi inaperekedwa chitsanzo pofufuza nthawi ya malire a KT (malire a Cretaceous-Paleogene), omwe amasonyeza nthawi ya kutha kwa zinthu zambiri. Malirewa amadziwika ndi dongo lopangidwa ndi iridium, lomwe limaganiziridwa kuti linachokera ku asteroid yomwe inachititsa kuti zinthu zambiri zithe. Umboni wa zinthu zakale kuchokera pamwamba ndi pansi pa gawoli, kuphatikizapo nthawi ya radiometric dating, unathandiza kuzindikira kuti chochitika choopsachi chinalipo zaka pafupifupi 66 miliyoni zapitazo.
Taphonomy ndi Udindo Wake mu Stratigraphy
Taphonomy, kuphunzira njira zomwe zimakhudza zamoyo pamene zikusintha kukhala mafupa, kumathandizanso pakupanga ma stratigraphy. Kumvetsetsa mikhalidwe ndi njira zomwe zimapangitsa kuti mafupa asinthe kumathandiza akatswiri a za nthaka kutanthauzira malo akale omwe adasungidwa komanso kusintha kwa majini. Mwachitsanzo, kuchuluka kwa mafupa a nsomba omwe asungidwa bwino mkati mwa stratum inayake kungasonyeze kuti akuikidwa m'manda mwachangu m'malo opanda mpweya (opanda mpweya), monga nyanja youma, zomwe zimaletsa kuwonongeka ndi kuchotsedwa kwa zinthu.
Kuphatikiza apo, maphunziro a taphonomic amatha kuwonetsa kusintha kwa pambuyo pa depositional, monga zotsatira za diagenesis (kusintha kwa thupi ndi mankhwala panthawi ya lithification) pa ubwino ndi kufalikira kwa mafupa a zokwiriridwa. Kuzindikira kumeneku ndikofunikira potanthauzira zolemba zakale ndikuzigwirizanitsa ndi mikhalidwe yayikulu ya stratigraphic.
Zovuta ndi Zolepheretsa
Ngakhale kuti zinthu zakale zomwe zinapezeka m'mabwinja zimapereka deta yofunika kwambiri pa kafukufuku wa stratigraphic, kugwiritsa ntchito kwake kumabweretsa mavuto. Zolemba zakale sizili zokwanira chifukwa cha tsankho losiyanasiyana, monga kusungidwa kosiyana ndi kusankhidwa kwa zitsanzo, zoletsa zachilengedwe, ndi njira za geology zomwe zingawononge kapena kubisa umboni wa zinthu zakale. Si mitundu yonse ya miyala yomwe ili ndi zinthu zakale, ndipo zamoyo zambiri sizipezeka m'mabwinja, zomwe zimapangitsa kuti zolembazo zikhale ndi mipata.
Komanso, kuyika kwa diachronous (matope omwe amaikidwa nthawi zosiyanasiyana m'malo osiyanasiyana koma kupanga gawo limodzi) kungapangitse kuti ntchito yogwirizanitsa ikhale yovuta. Ngakhale kuti pali zovuta izi, kugwiritsa ntchito bwino deta ya zakale, pamodzi ndi njira zina zowunikira, kungachepetse zina mwa zofookazi.
Kutsiliza
Zinthu zakale zimakhala ngati njira yodziwira mbiri yakale ya Dziko Lapansi, zomwe zimapereka chidziwitso chofunikira pa kusanthula kwa stratigraphic. Zimagwira ntchito ngati zizindikiro za nthawi, zizindikiro za chilengedwe, ndi zida zolumikizirana kwakukulu kwa geological. Kudzera mu kuphunzira mosamala ndi kutanthauzira umboni wa zinthu zakale zakale, akatswiri a geology amatha kukonzanso mbiri yakale ya dziko lathu lapansi, kuwulula zinsinsi za zachilengedwe zakale, kusintha kwa nyengo, ndi zochitika za geology. Ngakhale kuti mbiri ya zinthu zakale ikhoza kukhala yosakwanira, zopereka zake pakumvetsetsa stratigraphy ndizofunikira kwambiri, zomwe zimatsimikizira kufunika kwa paleontology m'dera lonse la sayansi ya Dziko Lapansi.
