Lokacin Ordovician

Ofaya daga cikin lokutan zamanin Paleozoic wanda yawanci ya kasance game da haɓakar teku da yaduwar rayuwa a cikin halittu masu rai. Lokacin Ordovician. Lokaci ne wanda yake nan da nan bayan Lokacin Cambrian kuma kafin hakan Siluriyanci. A wannan lokacin an sami raguwar rabe-raben halittu masu yawa a ƙarshen wanda ya haifar da taron ƙarewar taro.

A cikin wannan labarin za mu gaya muku duk halaye, ilimin ƙasa, yanayi, fure da fauna na zamanin Ordovician.

Babban fasali

Wannan lokacin ya ɗauki kimanin shekaru miliyan 21. Ya fara ne kimanin shekaru miliyan 485 da suka gabata kuma ya kasance har zuwa shekaru miliyan 433 da suka gabata. Yana da manyan sauyin yanayi tunda akwai babban bambanci tsakanin farawa a wasan ƙarshe. A farkon lokacin, yanayin zafi yayi yawa, amma sauye-sauyen muhalli da yawa sun faru wanda ya haifar da zamanin kankara.

Kamar yadda muka ambata a farkon labarin, akwai halaka mai yawa a ƙarshen lokacin wanda ya ƙare da kusan kashi 85% na dukkan nau'ikan halittun da suka wanzu a lokacin, musamman tsarin halittun ruwa.

Wannan lokacin ya kasu kashi uku: Lowerananan, na Tsakiya da Manyan Ordoviciyan.

Ordovician Geology

Ofaya daga cikin mahimman halaye game da ilimin ƙasa na wannan lokacin shine matakan tekun sun kasance mafi girma. Duk tsawon wannan lokacin akwai manyan kasashe 4: Gondwana, Siberia, Laurentia da Baltica. Kamar yadda yake a lokacin da ya gabata, kusan duk arewacin duniyar duniyar ta mamaye Tekun Panthalassa. Sasashen yankin Siberia kaɗan da wani ɗan ƙaramin yanki na Laurentia ne kawai aka samu a cikin wannan yanki na duniya.

Kudancin duniya, muna da yankin Gondwana wanda ya mamaye kusan dukkanin sararin samaniya. Hakanan akwai ɓangaren Baltica da Laurentia. Tekunan da suka wanzu a wannan lokacin sune: Paleo Tetis, Panthalasa, Lapetus da Rheico. Yawancin abubuwa sananne ne game da ilimin ƙasa na Ordovician daga burbushin dutsen da aka gano. Mafi yawan waɗannan burbushin ana samun su a cikin kankara mai ƙarancin ruwa.

Ofaya daga cikin abubuwan da aka sani sosai a wannan zamani shine Taconic orogeny. Wannan orogeny an samar dashi ne ta hanyar karo-karo na manyan kasashen biyu. Wannan haɗin ya ɗauki shekaru miliyan 10. Sakamakon wannan tsarin ilimin kasa, da Dutsen Appalachian.

Yanayin Ordovician

Kamar yadda aka ambata a baya, yanayin lokacin Ordovician yana da dumi da na wurare masu zafi. Musamman a farkon lokacin akwai yanayin zafi mai yawa, koda tare da alamun cewa akwai wurare tare da bayanan yanayin zafin jiki na digiri 60. Koyaya, a ƙarshen lokacin, yanayin zafi ya fara sauka ta yadda zai haifar da wani ƙyalli mai ƙyalli. Wannan kyalkyali yakai hari ne sosai akan manyan yankuna na Gwanawana. A wannan lokacin babbar nahiyar ita ce kudancin duniya. Glaciation yakai kimanin shekaru miliyan 1.5. Saboda wannan tsari na rage yanayin zafi, yawancin adadi na dabbobin sun bace wadanda basu iya daidaitawa da sabbin yanayin muhalli.

Akwai wasu karatuttukan da suka tabbatar da cewa kyalkyali har ila yau ya fadada zuwa Yankin Iberiya. Wannan yana nufin cewa imanin cewa kankara kawai ya bazu a yankunan pole na kudu za a musanta shi. Abubuwan da ke haifar da wannan ƙarancin gilashin har yanzu ba'a san su ba. Akwai magana game da raguwa a cikin ƙwayoyin carbon dioxide a matsayin mai yiwuwa sanadi.

vida

A lokacin Ordovician yawancin jinsi sun bayyana wanda ya haifar da sabon nau'in. Musamman rayuwa ta bunkasa a cikin teku. Zamu bincika flora da fauna daban.

Flora

La'akari da cewa mafi yawan rayuwa sun bunkasa ne a cikin yanayin ruwa, yana da ma'ana ayi tunanin cewa tsirrai sun sami cigaba mai kyau. Koren algae ya yadu a cikin tekuna. Hakanan akwai wasu nau'ikan fungi wadanda suka cika aikin narkar da kwayoyin halittar kwayoyin halitta. Wannan shine yadda teku zata iya daidaita kanta.

Tarihin samun tsarin ƙasa ya bambanta da na duniyar teku. Kuma flora kusan babu shi. Werean ƙananan smallan tsire-tsire ne kaɗan suka fara mallakar mulkin mallaka. Wadannan tsire-tsire sun kasance na asali kuma na asali. Kamar yadda ake tsammani, sun kasance ba jijiyoyin bugun jini, ma'ana, ba su da xylem ko phloem. Tunda ba tsire-tsire ne na jijiyoyin jini ba, yana buƙatar kasancewa kusa da kwasa-kwasan ruwa don samun damar wadatarwa. Wadannan nau'ikan tsire-tsire suna kama da hantawar hanta da muka sani a yau.

fauna

A zamanin Ordovician fauna da gaske suna da yawa a cikin teku. Akwai babban bambancin halittu daga mafi ƙanƙanta kuma mafi ƙarancin rayuwa zuwa wasu dabbobin da suka fi haɓaka da rikitarwa.

Mun fara yin kwalliya. Yana ɗaya daga cikin gefuna tare da wadataccen wadata a wannan lokacin. A cikin tsinkayen da muke samu trilobites, kunamai na teku da ƙwararrun masarufi, da sauransu. Mollusks suma sun sami babban fadada akan juyin halitta. Cephalopods, bivalves da gastropods sun mamaye cikin teku. Neededarshen na buƙatar matsawa zuwa gabar teku, amma da yake ba su da numfashin huhu, ba za su iya zama a cikin mazaunin ƙasar ba.

Amma ga murjani, sai suka fara tarawa don yin tsari murjani na farko da ya ƙunshi nau'ikan samfuran. Hakanan suna da nau'ikan soso iri daban-daban waɗanda suka kasance suna haɓaka yayin Cambrian.

Kawar da yawa daga Ordovician

Wannan ɓarkewar ɗimbin ya faru kusan shekaru miliyan 444 da suka gabata kuma ya ɓata ƙarshen zamanin Ordovician da farkon zamanin Silurian. Dalilin da yasa masana kimiyya suka faɗi haka shine:

• Ragewa cikin iskar carbon dioxide na yanayi. Wannan ya haifar da kyalkyalin duniya wanda ya rage yawan dabbobi da tsirrai.
• Ragewa a matakin teku.
• A glaciation kanta.
• Fashewar wata babbar kasuwa. Wannan ka'idar an kirkireshi a farkon shekaru goma na karni na XNUMX. Ya ce akwai fashewar abu a sararin samaniya daga wata kasa da ta haifar da ambaliyar gamma. Wadannan rawanin gamma sun haifar da raunin tsarin ozone da asara a siffofin rayuwar bakin teku inda akwai zurfin zurfi.

Ina fatan cewa tare da wannan bayanin zaku iya koyo game da zamanin Ordovician.