Munguva yese ye Mesozoic tinowana matatu nguva: iyo Triassic, the Jurassic and the Cretaceous. Nhasi ticha tarisa pakutaura nezve iyo Cretaceous nguva. Icho chidimbu cheiyero yenguva inoenderana neiyo nguva yegeological kuva nguva yechitatu neyekupedzisira yeMesozoic. Yakatanga angangoita mamirioni zana nemakumi mashanu emakore akapfuura uye yakapera makore angangoita mamirioni makumi matanhatu nemashanu apfuura. Iyi nguva yakakamurwa kuita mahafu maviri anozivikanwa seMuzasi Cretaceous uye Wekumusoro Cretaceous. Iyi ndiyo imwe yenguva refu kwazvo mukati meiyo Phanerozoic eon.
Muchikamu chino tiri kuzokuudza zvese zvaunoda kuti uzive nezve iyo Cretaceous nguva.
Mhando huru
Iyi nguva ine zita rayo kubva muchiLatin mu Eta zvinoreva choko. Iri zita rakavakirwa pamatanho ari muParisiti Basin muFrance. Munguva ino hupenyu mumakungwa nepanyika hwakaonekwa semusanganiswa wemhando dzese dzazvino uye mafomu echinyakare. Inotora anenge mamirioni makumi masere emakore inenge, iri nguva refu kwazvo yePanerozoic eon.
Semumazera mazhinji egeological atakadzidza, kutanga kwenguva ino hakuna chokwadi nemamirioni mashoma emakore zvakanyanya kana zvishoma. Kwese kwese kwese kunoperera uye kupera kwemagariro enguva kwakatemwa nechiitiko chakakosha chepasirese, kungave nekuchinja kwemamiriro ekunze, maruva, mhuka kana geology. Iko kufambidzana kwekuguma kwenguva ino kwakaringana zvine chekuita nekutanga. Izvi zvinodaro nekuti kana iwe uchifananidza imwe yeiyo geologic materu ayo ane yakasimba iridium kuvapo uye iyo inoita kunge inowirirana kudonha kwemeteorite mune izvo zvino zvinoenderana neYucatan Peninsula uye Gulf yeMexico.
Iyi ndiyo meteorite ine mukurumbira inogona kupedzisira yakonzeresa kutsakatika kwakaitika mukupera kwenguva ino umo chikamu chikuru chemhuka dzese chakanyangarika, kusanganisira ma dinosaurs. Ichi ndicho chiitiko chakakosha kupfuura zvese chinozivisa kupera kweMesozoic era. Zviri mushure meJurassic uye pamberi pe Paleocene.
Cretaceous zvemaumbirwo
Pakati pepakati peCretaceous, inopfuura hafu yematura epasi rose emafuta atinawo nhasi akaumbwa. Mazhinji emakanzuru ane mukurumbira ari kutenderedza Persian Gulf uye mudunhu riri pakati peGulf yeMexico nemahombekombe eVenezuela.
Munguva yese iyi mwero wegungwa waive wakaramba uchikwira nekuda kwekuwedzera kwetembiricha yepasirese. Uku kukura kwakatora mwero wegungwa kumatanho epamusoro akambonyorwa munhoroondo yepasi redu. Nzvimbo zhinji dzaimbove gwenga dzakava mafuro akazara nemvura. Chikamu chegungwa chakasvika pakadai zvekuti 18% chete yepasi pevhu yaive pamusoro pemvura. Nhasi tine 29% yenzvimbo yakabuda yenyika.
Iyo supercontinent inozivikanwa sePangea yakakamurwa mukati menguva yese yeMesozoic kupa kumakondinendi atinoziva nhasi. Nzvimbo dzavaibata panguva iyoyo dzaive dzakasiyana zvakanyanya. Pakutanga kweCretaceous kwaive kwatove nemaviri makuru makuru anozivikanwa saLaurasia naGondwana. Aya makuru makuru epasi akapatsanurwa neGungwa reThetis. Pakupera kwenguva ino makondinendi akatanga kutora mafomu akafanana zvakanyanya neazvino. Kupatsanurana kunofambira mberi kwemakondinendi kwakakonzerwa nekuita kweiyo Continental Drift uye ichiperekedzwa nekuumbwa kwenzvimbo dzakafara nematombo.
Iyo yekukanganisa system yaivapo mukati meJurassic yakanga yapatsanura Europe, Africa, neNorth America kondinendi. Zvisinei, idzi masasa epasi akaramba ari padhuze nepadhuze. India neMadagascar vaifamba kubva kumahombekombe eEast Africa. Chimwe chezvikamu zvakakosha zvekuputika kukuru kwakaitika pakati pekupedzisira kweCretaceous neyekutanga Paleocene muIndia. Kune rimwe divi, Antarctica neAustralia vaive vachiri pamwechete uye ivo vaifamba kubva kuSouth America vachikukurwa vakananga kumabvazuva.
Hwese kufamba uku kwakagadzira nzira nyowani dzegungwa senge yekutanga North uye Maodzanyemba eAtlantic zvakare, Gungwa reCaribbean uye Indian Ocean. Ipo nyanza yeAtlantic yaive ichikura, maogengenies aive akaumbwa panguva yeJurassic akaenderera mberi kubva kuNorth America makomo renji nepo Nevada orogeny ichiteverwa nemamwe maogengen akaita seLaramide.
Cretaceous ekunze
Tembiricha panguva ino yakakwira kusvika pakukwira kwazvo angangoita mamirioni zana emakore apfuura. Panguva iyoyo, pakange pasina chando pamapango. Iyo sediment yakawanikwa kubva panguva ino inoratidza kuti tembiricha iri pamusoro peiyo tropical Ocean inofanira kunge iri pakati pe100 ne9 degrees, ichidziya kupfuura zvazvino. Tembiricha mukati megungwa rakadzika inofanirwa kunge yaive yakatokwana gumi nemashanu uye makumi maviri madigiri.
Nyika haifanirwe kunge yaidziya zvakanyanya kupfuura panguva yeTriassic kana Jurassic, asi ichokwadi kuti tembiricha yekudziya iri pakati pematanda neEquator yaifanira kuve yakatsetseka. Uku kutonhora kutsetseka gradient kwakakonzera mhepo yemhepo mafashama ekuderera kudzikira uye zvakabatsira mukuderedza mafungu egungwa. Naizvozvo, paive nemakungwa mazhinji aive akamira kupfuura zvaari nhasi.
Mushure mekupera kweCretaceous nguva tembiricha yepakati yakatanga kudzikira kunonoka kwaive kuchikurumidza zvishoma nezvishoma uye mumamirioni ekupedzisira emakore avhareji yegore yakadzikira kubva pamadhigirii makumi maviri kusvika pamadhigirii gumi.
Flora nemhuka
Mhedzisiro yakakonzera kuti Pasi ripatsanurane kuita gumi nemaviri kana anopfuura masosi epasi akafarira kuvandudzwa kwezvisikwa zvipenyu nemiti. Mune vanhu ava, vakaumba kwavo vega kuzvitsuwa zvemakondinendi eUpper Cretaceous uye vakashanduka kuti vagadzire zvakawanda zvezvinhu zvipenyu zvepasi nepagungwa izvo zvatinoziva nhasi.
Ndinovimba kuti neruzivo urwu unogona kudzidza zvakawanda nezve iyo Cretaceous nguva.
Chirevo chakanaka asi nekuwanda kwekunyora nekunyora kukanganisa.