Abubuwan da suka faru na hyperthermal

Abubuwan da suka faru na hyperthermal

Wani abu mai zafi da ya dace da dumamawar duniya kwatsam a kan sikelin lokacin geologic.

Sakamakon irin wannan taron shine batun bincike da yawa saboda zasu iya zama kwatankwacin dumamar duniya ta yanzu.

Abubuwan da suka faru na hyperthermal

An bayyana farkon irin wannan nau'in a cikin 1991 daga wani sinadari da aka samo daga hakowa na shirin hako ruwa na Tekun (ODP) da aka gudanar a Antarctica a cikin Tekun Weddell . Wannan taron yana faruwa a kan iyakar Paleocene da zamanin Eocene kimanin shekaru miliyan 56 da suka wuce. Yanzu ana kiranta da Paleocene-Eocene Thermal Maximum (PETM). A yayin wannan taron, zafin tekun ya karu da fiye da 5 °C a kasa da shekaru 10,000.

Tun daga wannan binciken, an gano wasu abubuwan da suka faru na hyperthermal a cikin wannan ƙananan ɓangaren lokacin Paleogene:

• taron Dan-C2 a farkon mataki Danian na Paleocene, kimanin shekaru miliyan 65.2 da suka gabata, ainihin tushen Zamanin Cenozoic;
• taron Danian-Selandian a lokacin sauyawa tsakanin matakan Danian da Selandian na Paleocene, kimanin shekaru miliyan 61 da suka gabata;
• abubuwan da suka faru guda biyu da suka biyo bayan PETM a lokacin Eocene mafi kyawun yanayi: Eocene Thermal Maximum 2 (ETM2) kimanin shekaru miliyan 53.2 da suka gabata, da kuma Eocene thermal Maximum 3 (ETM3) kimanin shekaru miliyan 52.5 da suka gabata.[1]
  • Eocene Thermal Maximum 2 (ETM2) kimanin shekaru miliyan 53.2 da suka gabata,
  • da kuma Eocene Thermal Maximum 3 (ETM3) kimanin shekaru miliyan 52.5 da suka gabata.

Amma taron PETM ya kasance mafi yawan nazarin abubuwan da suka faru na hyperthermic.

Sauran abubuwan hyperthermic sun faru a ƙarshen mafi yawan glaciations na Quaternary. Wataƙila mafi shahara daga cikin waɗannan shine zafi na kwatsam wanda ke nuna ƙarshen Younger Dryas, wanda ya ga matsakaicin zafin jiki na shekara-shekara na digiri da yawa a ƙasa da ƙarni ɗaya.

Dalilan da suka haifar

Duk da yake sakamakon waɗannan abubuwan hyperthermic yanzu ana nazarin su sosai kuma an san su, har yanzu ana muhawara game da abubuwan da ke haifar da su.

An ambaci manyan waƙoƙi guda biyu, mai yiwuwa masu dacewa, don fara waɗannan dumi-daya na kwatsam:

• tilastawar orbital tare da tsawo da / ko gajeren zagaye na duniya mafi girma wanda ke jaddada bambance-bambance na yanayi kuma yana haifar da dumama duniya;
• aiki mai ban mamaki na dutsen wuta, musamman a lardin Arewacin Atlantic.

Sakamakon

An kiyasta dumamar ruwa saboda PETM, ga duk latitudes na duniya, tsakanin 4 da 5 ° C don ruwan teku mai zurfi da tsakanin 5 da 9 ° C don ruwa mai zurfi.  

Carbon da aka kama a cikin clathrates da aka binne a cikin tsaunuka masu tsawo ana fitar da su zuwa teku a matsayin methane (CH4) wanda zai hanzarta oxidize zuwa carbon dioxide (CO2).

Acidification na teku da rushewar carbonate

A sakamakon karuwar CO2 da aka narke a cikin ruwan teku, teku suna yin acid. Wannan yana haifar da rushewar carbonates; yaduwar duniya ta zama mai laushi. Wannan tsari yana faruwa a kasa da shekaru 10,000 yayin da zai ɗauki kimanin shekaru 100,000 don carbonate sedimentation ya koma matakin pre-PETM galibi ta hanyar kama CO2 ta hanyar mafi girman yanayin silicate a kan nahiyoyi.

Rashin jituwa na zagayawar teku

Matsakaicin δ13C na abubuwan da ke cikin isotope na carbonates waɗanda suka zama harsashi na benthic foraminifera sun nuna tashin hankali a cikin yaduwar teku a lokacin PETM a ƙarƙashin tasirin dumama duniya. Wannan canjin ya faru ne a cikin 'yan dubban shekaru. Komawa ga halin da ake ciki a baya, kuma ta hanyar ra'ayoyi mara kyau godiya ga "tushen CO2" na yanayin silicate, ya ɗauki kimanin shekaru 200,000.

Tasirin da ke tattare da dabbobi na ruwa

Duk da yake benthic foraminifera ya wuce ta Cretaceous-Tertiary extinction wanda ya faru kusan shekaru miliyan 66 da suka gabata ba tare da wahala ba, taron hyperthermic na PETM, shekaru miliyan 10 bayan haka, ya kashe su tare da bacewar 30 zuwa 50% na jinsunan da ke akwai.

Dumamar ruwan saman kuma yana haifar da eutrophication na yanayin marine wanda ke haifar da haɓaka da sauri ta hanyar ingantaccen ra'ayi na CO watsi.

Tasirin da ke faruwa a kan dabbobi na duniya

Dabbobi masu shayarwa waɗanda suka sami babban ci gaba bayan ƙarewar ƙarshen Cretaceous za su shafar yanayin zafi na Paleogene. Yanayin zafi yana ƙaruwa kuma ya haifar da canje-canje na yanayi yana canza tsire-tsire da yawan abincin da ke akwai ga masu cin ganyayyaki. Wannan shine yadda yawancin kungiyoyin dabbobi masu shayarwa suka bayyana a farkon Eocene, kimanin shekaru miliyan 56 da suka gabata:

• Artiodactyls;
• Perissodactyls;
• Primates;
• Hyaenodontidae...

Misalai tare da dumamar duniya ta yanzu

Ko da abubuwan da suka faru na hyperthermal na Paleogene sun bayyana sosai a kan sikelin lokacin geologic (a cikin kewayon 'yan dubban shekaru don karuwar tsari na 5 ° C), sun kasance da yawa fiye da lokacin da aka yi la'akari da shi a cikin samfuran yanzu na dumamar duniya na asalin ɗan adam. 

Nazarin daban-daban na abubuwan da suka faru na hyperthermal sun nace kan abubuwan da suka haifar da sakamako mai kyau wanda, bayan farawar dumama, ya hanzarta shi sosai.