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Alamun Yanayi na Duniya

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Alamun Yanayi na Duniya
paleoclimate (en) Fassara

Alamun paleoclimate na duniya sune masu saurin ji ga canje-canjen yanayin paleoclimatic na duniya. Yawancin su an samo su ne daga ruwan da ke cikin ruwa. Alamun Paleoclimate da aka samo daga turɓaya na ƙasa, a gefe guda, galibi suna rinjayar motsi na gida da bambancin paleogeographic. Abubuwan da ke kula da tsarin yanayi na Duniya sun haɗa da tectonics na farantin, wanda ke sarrafa tsarin nahiyoyi, hulɗa tsakanin yanayi da teku, da halaye na duniya (Milankovitch cycles). An kafa alamun paleoclimate na duniya bisa ga bayanan da aka cire daga nazarin kayan ilimin ƙasa, gami da bayanan halitta, geochemical da ma'adanai da aka adana a cikin ruwa. Ana rarraba masu nunawa zuwa kashi uku; paleontological, geochemical da lithological.

Alamun paleontological

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Rubutun sedimentary suna da tasiri ta hanyar hoto na gida da na teku da na yanayi. Abubuwan da ke da mahimmancin yanayin yanayi na duniya, duk da haka, ba su da ma'ana a fassarar yanayin zafi. Marine biota sun bayar da nisa mafi yawan proxies ga paleotemperature, wanda microfossils, saboda tartsatsi, yalwa da kuma kula da latitude canje-canje, sun bayar da yawa na farko muhimman paleotemperature Manuniya. Gane nau'in fihirisar latitude yawanci shine ƙoƙari na farko na ɗaure kasancewarsu a cikin sediments zuwa canjin yanayin zafi. Sauran kaddarorin biota na ruwa, gami da ilimin halittar jiki, yalwa, bambance-bambance, da ilimin kimiyyar lissafi suma an samu nasarar kafa su azaman alamomin burbushin halittu. Ƙididdigar ƙididdigar ƙididdiga masu rikitarwa (binciken factor, babban sashi, da sauransu) na tarihin tarihin rayuwa sun sami damar haɗa tarukan fauna da yawan ruwa don sake gina paleo-na yanzu. Jerin da ke ƙasa akwai wasu mahimman kayan aikin burbushin halittu waɗanda masana kimiyya ke amfani da su don sake gina tarihin yanayin zafin jiki.

Yanayin Yanayi

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Girma
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Bincike na yawan planktonic foraminiferal ya nuna cewa nau'in wurare masu zafi sun kai girman gwajin su mafi girma a cikin ruwan zafi, kuma nau'in polar sun kai matsakaicin girman a cikin ruwan polar. Dabbobi da ke zaune a cikin ruwa mai zafi da ruwa mai zurfi suna raguwa a girman gwaji tare da karuwa da raguwar zafin jiki.[1]

Girman proloculus (ɗaki na farko) na forams na benthic yana shafar zafin ruwan teku kuma an yi amfani da matsakaicin su azaman wakili don binciken paleoclimatic.[2]

An yi amfani da matsakaicin gwajin gwajin planktonic foraminifer Orbulina universa don fassara tarihin zafin jiki na teku a cikin Basin Somaliya. R-mode factor da Q-mode cluster analysis sun bayyana manyan abubuwa guda biyar da kuma clusters biyar nuna daban-daban muhalli halaye, gami da kara oxygenation, high surface productivity.[3]

Hanyar juyawa
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An ambaci forams da yawa don samun hanyoyi daban-daban na juyawa don mayar da martani ga zafin jiki. Globierina pachyderma, alal misali, yana nuna yawan jama'a na dama a cikin ruwa mai sanyi vs. hagu a cikin ruwa ozu, [4] kuma an yi amfani da rabo na waɗannan siffofin biyu don kimanta yanayin zafi. [5][6] An bayar da rahoton irin wannan dogaro da jagororin juyawa akan yanayin zafi ga Muricohebergella delrioensis a cikin sediments na Cretaceous . [7]

Globigerina bulloides, wani benthic foram, an rubuta shi don hanyoyin da ke da alaƙa da yanayin zafi na ruwan teku a cikin turɓaya na kudancin Tekun Indiya.[8]

An rubuta irin wannan dangantakar don wani benthic foram Bulinina marginata . [9]

Bambancin nau'o'i

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Bambancin nau'ikan foraminiferal na Planktonic ya dogara da wuraren da ke akwai, waɗanda ke da alaƙa da yaduwar teku. Ta hanyar alaƙa da rikodin isotope mai ɗorewa, an sami matsakaicin bambancin ya faru bayan farawar lokacin glaciation.[10]

Tarihin rayuwa

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Tun lokacin da zurfin teku ya zama samuwa a cikin shekarun 1960, an yi amfani da alamun paleoclimatic na planktonic foraminifera daga ruwan teku don sake gina paleoclimate. Daga cikin majagaba na farko don amfani da wadataccen latitudinal foraminifera, Ericson da Wollin (1968) sun yi nasara wajen kafa sake zagayowar glacial da Interglacial na Pleistocene bisa ga rabo na nau'in ruwa mai sanyi da mai dumi a cikin turɓaya mai zafi.[11] Kennett (1970), wanda, bisa ga nau'in foraminferal na sanyi da ruwan dumi, ya sake gina canje-canjen paleoclimatic a cikin Pleistocene, daidai da yanayin da aka kafa a yankin wurare masu zafi.[12]

Lokacin da ake hakowa, wanda ya dawo da ginshiƙai masu tsawo fiye da piston, ya zo, an tura binciken sake fasalin paleoclimatic a lokutan geological. An gina yanayin yanayi a cikin Oligocene a cikin Gulf of Mexico ta hanyar amfani da alamun ruwa mai dumi (Turborotalia pseudoampliapertura, Globoquadrina tripartita, Dentoglobigerina globularis, Dentglobigerina baroemoenensis, "Globigerina" ciperoensis da Globigerinoides, da kuma Cassigerinella chipolensis) da alamun ruwan sanyi (Catapsydrax spp., Globorotaloides spbotp., Subs, sitel, stripgerides da Globi.[13] Spezzaferri ya binciki wani yanki mai zurfi a cikin 1995, wanda ya bincika samfurori daga ƙwayoyin hako a cikin Tekun Atlantika, Indiya da Kudancin Pacific kuma ya gano kuma ya haɗa foraminifera a cikin ƙididdigar zafi, sanyi, zafi da sanyi. An kafa tsarin yanayi na paleoclimatic a cikin lokacin canjin Oligocene da Miocene kuma bayanan isotope sun goyi bayan tsarin.[14]

Hanyar da ta fi dacewa don sake gina yanayin yanayi ya haɗa da amfani da bincike. Thompson (1981) ya sami damar danganta tarurruka shida na foraminiferal daga samfurori na farko don gabatar da ruwa a yammacin Arewacin Pacific. An samar da aikin canja wurin don haɗa tarurruka zuwa yanayin zafi na teku. An sake gina tsarin yanayin yanayi na shekaru 150,000 da suka gabata ta hanyar amfani da wannan aikin canja wurin ga tsoffin turɓaya a cikin ƙwayoyin.[15]

An yi amfani da irin wannan dabarar ga Eocene da Oligocene kuma an rarraba forams a cikin farfajiyar, matsakaici da zurfin ruwa. Ta haka ne aka sake gina nau'ikan ruwa, ban da sauye-sauyen yanayin yanayi.[16]

Coccolith

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An lura da canjin digiri 15 na latitude don rarraba wasu nau'ikan da aka zaɓa na Coccolits tsakanin abubuwan da suka faru a baya-bayan nan da kuma abubuwan da suka dace a tsakiyar Wisconsin na Arewacin Atlantic.[17] Haɗuwa da coccoliths a cikin ruwa na ruwa ya bayyana yana da alaƙa da yanayin zafi. Wannan an nuna shi ta hanyar bincike mai yawa na tarin coccolith a yammacin Bahar Rum Pleistocene.[18]

Masu amfani da rediyo

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Saboda tsayayyarsu ga rushewar ruwan sanyi, wanda ke lalata burbushin planktonic na calcareous a zurfin duniya, Radiolarians ya zama ɗaya daga cikin burbushin siliceous planktonics da aka fi nazarin don sake fasalin paleotemperature. Nazarin Radiolarians a cikin zurfin teku na Arewacin Pacific ya nuna cewa karuwa a cikin nau'o'in jinsuna da yawa da suka dace da manyan abubuwan da suka faru na glaciation na shekaru miliyan 16 da suka gabata. Canje-canje a cikin abubuwan da ke cikin Radiolarian suna bayyane don nunawa a cikin zafin jiki na teku gaba ɗaya.[19]

Ta hanyar amfani da nazarin kididdiga (Q-mode factor analysis), yawancin nazarin ƙididdigar ƙididdigat na Radiolarian daga turɓaya na ƙasa sun kafa aikin canja wurin wanda ke ba da damar kimanta yawan zafin jiki na paleo-sea. Misali, Pisias et al. (1997) sun sami damar gano tarin da ke wakiltar tarihin rayuwa na yanzu na Pacific kuma sun yi amfani da waɗannan tarin don hango hasashen zafin teku na iyakar glacier na ƙarshe.[20]

Manazarta

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  1. ↑ Hecht, Alan D. (25 June 1976). "Size Variations in Planktonic Foraminifera: Implications for Quantitative Paleoclimatic Analysis". Science. 192 (4246): 1330–1332. Bibcode:1976Sci...192.1330H. doi:10.1126/science.192.4246.1330. PMID 17739837.
  2. ↑ Nigam, Rajiv; Rao, Aradhana S. (1 May 1987). "Proloculus size variation in recent benthic Foraminifera: Implications for paleoclimatic studies". Estuarine, Coastal and Shelf Science. 24 (5): 649–655. Bibcode:1987ECSS...24..649N. doi:10.1016/0272-7714(87)90104-1.
  3. ↑ Gupta, A. K. (1 July 1997). "Paleoceanographic and paleoclimatic history of the Somali Basin during the Pliocene-Pleistocene; multivariate analyses of benthic foraminifera from DSDP Site 241 (Leg 25)". The Journal of Foraminiferal Research. 27 (3): 196–208. Bibcode:1997JForR..27..196G. doi:10.2113/gsjfr.27.3.196.
  4. ↑ Ericson, David B. (24 July 1959). "Coiling Direction of Globigerina pachyderma as a Climatic Index". Science. 130 (3369): 219–220. Bibcode:1959Sci...130..219E. doi:10.1126/science.130.3369.219. PMID 17816141. S2CID 29077070.
  5. ↑ (James D. ed.). Missing or empty |title= (help)
  6. ↑ Thompson, Peter R.; Shackleton, Nicholas J. (October 1980). "North Pacific palaeoceanography: late Quaternary coiling variations of planktonic foraminifer Neogloboquadrina pachyderma". Nature. 287 (5785): 829–833. Bibcode:1980Natur.287..829T. doi:10.1038/287829a0. S2CID 4321896.
  7. ↑ Desmares, Delphine; Crognier, Nemo; Bardin, Jérémie; Testé, Marc; Beaudoin, Bernard; Grosheny, Danièle (March 2016). "A new proxy for Cretaceous paleoceanographic and paleoclimatic reconstructions: Coiling direction changes in the planktonic foraminifera Muricohedbergella delrioensis" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology. 445: 8–17. Bibcode:2016PPP...445....8D. doi:10.1016/j.palaeo.2015.12.021.
  8. ↑ Malmgren, Björn A.; Kennett, James P. (1978). "Late Quaternary Paleoclimatic Applications of Mean Size Variations in Globigerina bulloides d'Orbigny in the Southern Indian Ocean". Journal of Paleontology. 52 (6): 1195–1207. JSTOR 1303930.
  9. ↑ Collins, Laurel S. (June 1990). "The correspondence between water temperature and coiling direction in Bulimina". Paleoceanography. 5 (3): 289–294. Bibcode:1990PalOc...5..289C. doi:10.1029/PA005i003p00289.
  10. ↑ Ottens, Janneke J.; Nederbragt, Alexandra J. (April 1992). "Planktic foraminiferal diversity as indicator of ocean environments". Marine Micropaleontology. 19 (1–2): 13–28. Bibcode:1992MarMP..19...13O. doi:10.1016/0377-8398(92)90019-G.
  11. ↑ Ericson, David B.; Wollin, Goesta (13 December 1968). "Pleistocene Climates and Chronology in Deep-Sea Sediments: Magnetic reversals give a time scale of 2 million years for a complete Pleistocene with four glaciations". Science. 162 (3859): 1227–1234. doi:10.1126/science.162.3859.1227. PMID 17756330.
  12. ↑ Kennett, James P. (February 1970). "Pleistocene paleoclimates and foraminiferal biostratigraphy in subantarctic deep-sea cores". Deep Sea Research and Oceanographic Abstracts. 17 (1): 125–140. Bibcode:1970DSRA...17..125K. doi:10.1016/0011-7471(70)90092-6.
  13. ↑ Spezzaferri, Silvia; Premoli Silva, Isabella (February 1991). "Oligocene planktonic foraminiferal biostratigraphy and paleoclimatic interpretation from Hole 538A, DSDP Leg 77, Gulf of Mexico". Palaeogeography, Palaeoclimatology, Palaeoecology. 83 (1–3): 217–263. Bibcode:1991PPP....83..217S. doi:10.1016/0031-0182(91)90080-B.
  14. ↑ Spezzaferri, Silvia (March 1995). "Planktonic foraminiferal paleoclimatic implications across the Oligocene-Miocene transition in the oceanic record (Atlantic, Indian and South Pacific)". Palaeogeography, Palaeoclimatology, Palaeoecology. 114 (1): 43–74. Bibcode:1995PPP...114...43S. doi:10.1016/0031-0182(95)00076-X.
  15. ↑ Thompson, Peter R. (1981). "Planktonic foraminifera in the Western North Pacific during the past 150 000 years: Comparison of modern and fossil assemblages". Palaeogeography, Palaeoclimatology, Palaeoecology. 35: 241–279. Bibcode:1981PPP....35..241T. doi:10.1016/0031-0182(81)90099-7.
  16. ↑ Keller, Gerta (August 1983). "Paleoclimatic analyses of middle Eocene through Oligocene planktic foraminiferal faunas". Palaeogeography, Palaeoclimatology, Palaeoecology. 43 (1–2): 73–94. Bibcode:1983PPP....43...73K. doi:10.1016/0031-0182(83)90049-4.
  17. ↑ McIntyre, Andrew (8 December 1967). "Coccoliths as Paleoclimatic Indicators of Pleistocene Glaciation". Science. 158 (3806): 1314–1317. Bibcode:1967Sci...158.1314M. doi:10.1126/science.158.3806.1314. PMID 17801859. S2CID 29899719.
  18. ↑ Flores, J. A.; Sierro, F. J.; Francés, G.; Vázquez, A.; Zamarren˜o, I. (1 February 1997). "The last 100,000 years in the western Mediterranean: sea surface water and frontal dynamics as revealed by coccolithophores". Marine Micropaleontology. 29 (3): 351–366. Bibcode:1997MarMP..29..351F. doi:10.1016/S0377-8398(96)00029-1.
  19. ↑ Kamikuri, Shin-ichi; Nishi, Hiroshi; Motoyama, Isao (June 2007). "Effects of late Neogene climatic cooling on North Pacific radiolarian assemblages and oceanographic conditions". Palaeogeography, Palaeoclimatology, Palaeoecology. 249 (3–4): 370–392. Bibcode:2007PPP...249..370K. doi:10.1016/j.palaeo.2007.02.008.
  20. ↑ Pisias, Nicklas G.; Roelofs, Adrienne; Weber, Mysti (June 1997). "Radiolarian-based transfer functions for estimating mean surface ocean temperatures and seasonal range". Paleoceanography. 12 (3): 365–379. Bibcode:1997PalOc..12..365P. doi:10.1029/97PA00582.
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