Tsarin Morrison

**Tsarin Morrison** wani tsari ne na musamman na Dutsen Jurassic sedimentary dutse da aka samu a yammacin Amurka wanda ya kasance tushen tushen burbushin dinosaur a Arewacin Amurka. Ya ƙunshi dutsen laka, dutsen yashi, dutsen siltstone, da farar ƙasa kuma yana da haske mai launin toka, koren launin toka, ko ja. Yawancin burbushin halittu suna faruwa ne a cikin gadaje siltstone koren da ƙananan duwatsun yashi, abubuwan koguna da wuraren ambaliya na zamanin Jurassic .

Tana tsakiya a Wyoming da Colorado, tare da filaye a Montana, North Dakota, South Dakota, Nebraska, Kansas, panhandles na Oklahoma da Texas, New Mexico, Arizona, Utah, da Idaho . Ana samun makamantan duwatsun da ke ƙarƙashin sunaye daban-daban a Kanada.  Ya ƙunshi yanki na 1.5&nbsp;murabba'in kilomita miliyan (600,000&nbsp;murabba'in mil), ko da yake ƙaramin juzu'i ne kawai aka fallasa kuma ana iya samun dama ga masana ilimin ƙasa da masana burbushin halittu . Fiye da kashi 75% har yanzu ana binne su a ƙarƙashin ciyawar da ke gabas, kuma yawancin fa'idodin fassarori na yamma sun lalace yayin haƙon tsaunin Rocky .

An ba shi suna bayan Morrison, Colorado, inda Arthur Lakes ya gano wasu daga cikin burbushin farko a cikin samuwar a cikin 1877. A wannan shekarar, ta zama cibiyar yakin Kashi, kishiya mai tattara burbushin halittu tsakanin masana burbushin halittu na farko Othniel Charles Marsh da Edward Drinker Cope . A Colorado, New Mexico, da Utah, Morrison Formation shine babban tushen ma'adinin uranium .

## Tarihin Geologic
Dangane da sadarwar rediyo, Morrison Formation ya fara daga 156.3&nbsp;±&nbsp;2&nbsp;shekaru miliyan ( Ma ) a gindinsa,  zuwa 146.8&nbsp;±&nbsp;1&nbsp;shekaru miliyan a saman,  wanda ke sanya shi a farkon Kimmeridgian, da farkon matakan Tithonian na marigayi Jurassic. Wannan yayi kama da shekarun Solnhofen Limestone Formation a Jamus da Tsarin Tendaguru a Tanzaniya . Shekaru da yawancin dabbobi sun yi kama da Tsarin Lourinhã a Portugal.  A cikin yammacin Amurka, ya bambanta da Jurassic Summerville ta Tsakiya, Sundance, Bell Ranch, Wanakah, da Tsarin Stump.

A lokacin, babban nahiyar na Laurasia kwanan nan ya rabu zuwa nahiyoyi na Arewacin Amirka da Eurasia, kodayake har yanzu suna hade da gadoji na ƙasa. Arewacin Amurka ya koma arewa kuma yana wucewa ta yankuna masu zafi .

Morrison Basin, wanda ya tashi daga New Mexico a kudu zuwa Alberta da Saskatchewan a arewa, an kafa shi a lokacin Nevadan orogeny, wani abin da ya faru a baya zuwa abubuwan da ke faruwa na orogenic wanda ya haifar da Dutsen Rocky ya fara turawa zuwa yamma. Adadin da aka samu daga magudanan ruwa na gabas, wanda koguna da koguna daga tsaunukan Elko (tare da kan iyakokin Nevada da Utah na yau) kuma an ajiye su a cikin rairayin bakin teku, tafkuna, tashoshi na kogi da ambaliyar ruwa, sun zama Morrison Formation. 

A arewa, Tekun Sundance, tsawo na Tekun Arctic, ya shimfiɗa ta Kanada har zuwa Amurka. Ana samun gawayi a cikin Morrison Formation na Montana, wanda ke nufin cewa yankin arewa na samuwar, kusa da gabar teku, ya kasance jika da fadama, tare da karin ciyayi. Aeolian, ko kuma yashi na iska, ana samun su a yankin kudu maso yamma, wanda ke nuna cewa ya fi bushe-bushe - hamada, tare da dunƙulen yashi.

## Dabaru

Tsarin Morrison ya kasu kashi cikin mambobi da yawa, abin da ya faru ya bambanta a fadin yankin Morrison. Membobi ne (a cikin jerin haruffa):  

* Bluff Sandstone Member (AZ, CO, NM, UT): An tsara shi da kyau, launin ruwan kasa mai launin ruwan kasa zuwa farin yashi tare da manyan hatsi da sassan chert. Fassara kamar yadda ake ajiyewa a cikin saitin aeolian, a gefen filin dune. 

* Memba na Basin Basin (AZ, CO, NM, UT): haɗin gwiwar haɗin gwiwa tare da dutsen laka; zuwa kashi hamsin bisa dari ta juzu'i yana kunshe ne da ash da aka canza, wanda ya samo asali yayin da tokar felsic ta fadi. Ƙila ya faru a cikin yanayin fluvial-lacustrine, tare da ɓangaren lacustrine yana kula da wasan kwaikwayo . 
* Memba na Fiftymile (UT): Yafi kasancewa a cikin kwandon Kaiparowits, wanda ya ƙunshi dutsen yashi tare da dutsen laka, tare da ƙaramin taro. A cikin gida, shine memba mafi girma kuma yana da lamba tare da Tsarin Dakota . 
* Memba na Jackpile Sandstone (NM): da farko farar dutsen yashi mai ƙetare gado tare da matrix yumbu. An haɗa shi tare da bambance-bambance, kodadde-kore zuwa ja, ruwan tabarau na laka na bentonic.  Koyaya, sakamakon binciken geochronology na kwanan nan na detrital zircon ya nuna cewa Memba na Jackpile Sandstone yana cikin Tsarin Burro Canyon .  
* Memba na Ralston Creek (CO): wanda a da an yi la'akari da shi daban kuma kwanan nan aka sake shi azaman memba na basal na Morrison a gabashin Colorado. Ya bayyana kama da Tidwell da Membobin Wanke Gishiri. Ana samun goyan bayan wannan sake rarrabawa ta ƙarin cikakken bincike na lambobin sadarwa da saduwar rediyo. Ralston Creek ya ƙunshi conglomerate, sandstone, gypsum-mudstone, da gypsum-sandstone-laka facies; Ba a ƙayyade idan gypsum na marine ko lacustrine ba ne. 
* Memba na Sake Kamo (AZ, CO, NM, UT): yana samar da kasan Morrison a cikin mafi yawan kewayon sa, yana wuce gona da iri na Entrada da Wanakah .  Ya ƙunshi dutsen yashi mai yumbu da dutsen yumbu, wanda ke wakiltar yanayin daɗaɗɗa, wanda aka haɗa tare da facies na aeolian kawai;  a wurare, kuma ya ƙunshi babban (har zuwa kashi goma sha tara) na haɓakar orthoclase feldspar. 
* Memba Wanke Gishiri (CO, UT): wanda ya ƙunshi dutsen yashi mai laushi,  tare da halaye na lokaci-lokaci. 

* **Memba na Tidwell** (AZ, CO, NM, UT): a arewacin yankin Colorado Plateau, shine memba na basal na Morrison. Ya ƙunshi babban dutsen siltstone, shale, da dutsen yashi, kuma lokaci-lokaci yana haɗa ƙullun dutsen ƙasa, tare da gadaje masu bakin ciki na farar ƙasa.  Wuraren ɓoyewa sun bambanta daga laka har zuwa fluvial, don ƙafe da lacustrine . Morrison gabaɗaya yayi kama da Tidwell. 
* Unkpapa Sandstone Memba (SD): yana faruwa da farko a yammacin Dakota ta Kudu a matsayin tsayayyen dutsen yashi mai kyau, wanda ya ƙunshi ma'adini na farko, tare da wasu abubuwan haɗin feldspar.  An mamaye gida ta hanyar Lakota Formation ko babban jikin Morrison, kuma ya mamaye Redwater Shale Member na Sundance Formation .  Lokaci-lokaci ana magana da shi azaman tsari daban, musamman a cikin yankin Black Hills . 
* Memba na Westwater Canyon (AZ, CO, NM, UT): ya ƙunshi dutsen yashi tare da ruwan tabarau na laka da ɓangaren haɗin gwiwar lokaci-lokaci. Ajiye a cikin yanayin ƙwanƙwasa-rafi, mai girma a cikin kwayoyin halitta. Kalmar "Poison Canyon Sandstone" ana amfani da ita ba bisa ƙa'ida ba ga sassan dutsen yashi na sama na memba.  Memba na Westwater Canyon shine babban tushen ma'adinin uranium a cikin Morrison, musamman a cikin San Juan Basin . 
* Memba na Windy Hill (CO, SD, UT, WY): An haɗa shi a matsayin babban memba na Tsarin Sundance, kamar yadda, kamar sauran Sundance, an adana shi a cikin saitunan ruwa; duk da haka, an raba shi da rashin daidaituwa da tsoma baki tare da Morrison, wanda ya cancanci canjin nomenclature.  Ya ƙunshi lemun tsami, yashi mai kasusuwa, wanda gabaɗaya ana fassarawa don adanawa a cikin yanayin ruwa. 

Sauran ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙa'idodin Morrison sun haɗa da Stockett Bed a cikin Montana, rukunin rukunin da ba na hukuma ba wanda ya ƙunshi gawayi bituminous;  tsoffin kalmomin Casamero, Chavez, da Prewitt Sandstone don Brushy Basin, Recapture, da Westwater Canyon, bi da bi;   da Memba na Bullington, wanda aka yi watsi da shi gaba daya.

## Abun cikin burbushin halittu

Kodayake yawancin burbushin Morrison Formation sun rabu, sun isa su samar da kyakkyawan hoto na flora da fauna a cikin Morrison Basin a lokacin Kimmeridgian. Gabaɗaya, yanayin ya bushe, kama da savanna amma, tunda babu angiosperms ( ciyawa, furanni, da wasu bishiyoyi ), flora ya bambanta sosai. Conifers, tsire-tsire masu rinjaye na lokacin, an samo su tare da ginkgos, cycads, ferns bishiyoyi, da kuma doki . Mafi yawan ciyayi da aka ruguje sun kasance magudanan ruwa, suna zaune a gefen filayen kogin. A gefen kogunan akwai kifaye, kwaɗi, salamanders, ɗigo, kada, kunkuru, pterosaurs, crayfish, clams, da mammaliforms .

Dinosaurs sun kasance masu yuwuwar rafi, haka nan.  An gano daruruwan burbushin dinosaur, irin su *Allosaurus*, *Ceratosaurus*, *Torvosaurus*, *Camptosaurus*, *Ornitholestes*, da dama stegosaurs wanda ya ƙunshi akalla nau'i biyu na *Stegosaurus* da ɗan ƙaramin *Hesperosaurus*, da kuma farkon ankylosaurusurus *, da kuma farkon ankylosurusurusaurs* *.* musamman nau'in sauropods (kattai na zamanin Mesozoic ).  Tun da aƙalla wasu daga cikin waɗannan nau'in an san sun kasance a cikin yanki (An gano embryoes *na Camptosaurus* ), akwai alamun cewa yanayi ne mai kyau ga dinosaur kuma ba kawai gida ga ƙaura ba, yawan al'umma na yanayi. Duk da haka, an fassara babban taro na sauropods a matsayin daidaitawa ga ƙaura a lokutan fari. 

Sauropods da aka gano sun hada da *Diplodocus* (mafi shahara, na farko kusan cikakken samfurin *D. carnegii*, wanda aka nuna a yanzu a Carnegie Museum of Natural History, a Pittsburgh, Pennsylvania), *Camarasaurus* (wanda aka fi samu sauropod), *Brachiosaurus*, *Apatosaurus*, *Brontosaurus*, *Brontosaurus* *Haplocanthosaurus* da *Supersaurus* . Bambancin sauropods ya haifar da wasu tambayoyi game da yadda za su iya kasancewa tare. Yayin da surar jikinsu ta yi kama da juna (dogon wuya, doguwar wutsiya, babbar jiki irin ta giwa), ana kyautata zaton sun sami dabarun ciyarwa daban-daban, domin kowa ya wanzu a lokaci guda da kuma yanayi iri daya.

### Shafukan yanar gizo da ma'auni

Wuraren da aka yi mahimman binciken burbushin halittu na Morrison Formation sun haɗa da:

#### Colorado

* Lambun Lambun, Colorado : Daya daga cikin manyan wurare uku da masana burbushin halittu Othniel Charles Marsh da Edward Drinker Cope suka tono a lokacin Yaƙin Kashi a 1877, kodayake yawancin samfuran ba su cika ba don rarraba ( *nomina dubia* ) a lokacin lokutan filin 1877-78. An gano farkon kusan cikakkiyar kwarangwal na *Stegosaurus, Ceratosaurus ,* da *Allosaurus* a wurin, gami da nau'ikan samfurori na tsoffin biyu da kuma tsarin neotype na *Allosaurus fragilis,* a cikin 1883-1886 Yale filin yanayi.  A cikin 1992, an gano wani samfurin *Stegosaurus stenops* tare da makamansa har yanzu, wanda ya tabbatar da cewa dinosaur yana da faranti guda biyu a bayansa.
* Dry Mesa Quarry, Colorado: Dabbobin dabbobi iri-iri, da kuma mafi yawan nau'ikan nau'ikan dinosaur daga duk wani dutsen Morrison Formation. Na farko tono ya kasance a cikin 1972, ta masu bincike daga Jami'ar Brigham Young . Musamman samfurori sun hada da dinosaur mafi tsawo da aka sani, *Supersaurus*, da  *Ultrasauros*, da kuma mafi girma na dabba a nahiyar, *Torvosaurus* .
* Yankin Albarkatun Paleontological Fruita: Shafukan Badlands da ke kudu da Fruita, George Callison daga Jami'ar Jihar California da Gidan Tarihi na Tarihin Halitta na Los Angeles County ne suka yi aiki da shi. An samu samfurori da dama na dabbobi masu shayarwa, kadangaru, da na kada. Kwanan nan, *Fruitafossor windscheffelia* da sabon dinosaur *Fruitaden* an kwatanta su daga yankin.
* Wurin waƙa na Kogin Purgatoire, Otero County .

#### Utah

* Cleveland-Lloyd Dinosaur Quarry, Utah: Masana ilimin ƙasa sun fara tono shi daga Jami'ar Utah a ƙarshen 1920s. William Lee Stokes ya jagoranci wani balaguro daga Princeton a cikin 1939. A lokacin Jurassic, quarry ya kasance mai yiwuwa wani tafki mai ban mamaki, inda dinosaur suka taru suka mutu saboda tsananin fari.  An sake yin aikin gawawwakin su ta hanyar abubuwan ambaliya na yanayi, wanda kuma ya kara da wasu gawawwaki daga wasu wurare.  *Allosaurus fragilis* shine mafi yawan dinosaur na yau da kullun a wannan rukunin yanar gizon, yana mai da shi ƙirar ƙirar ƙira don nazarin ilimin halittu a cikin basal theropods. An fara gano nau'ikan nau'ikan nau'ikan nau'ikan *Stokesosaurus* da na *Marshosaurus* a nan.
* Dinosaur National Monument, Utah: Da farko Earl Douglas ya tono shi yana aiki don Gidan Tarihi na Carnegie a 1909 tare da manufar gano sauropods daga Morrison Formation don nunawa jama'a. Har ila yau, abin tunawa ya haifar da burbushin dinosaur daga Tsarin Dutsen Cedar .
* Gidajen haya a Hanksville-Burpee Quarry, Hanksville

#### Wyoming

* Kashi Cabin Quarry, Wyoming
* Como Bluff, Wyoming: Ɗaya daga cikin shahararrun wuraren burbushin halittu a Arewacin Amirka. An fara aiki da Cope da musamman Marsh a cikin 1877 kuma ya kasance tushen yawancin sauropods daban-daban da nau'ikan da ba na dinosaur ba. Tsarin Cloverly daga Cretaceous da wasu nau'ikan Triassic suma an fallasa su a wannan wurin.
* Cibiyar Dinosaur Wyoming, Thermopolis
* Barci Goma, gami da Dana Quarry daga inda aka kwato aƙalla sauropods 12 da kuma theropods. 

#### Montana

* Ranar Mahaifiyar Quarry, Carbon County

## Ilimin tattalin arziki
Morrison Formation yana ƙunshe da adibas na uranium, gami da jikin Jackpile uranium da aka gano kusa da Grants, New Mexico a 1951.  Abubuwan da ake ajiyar tama a cikin bel ɗin ma'adinai na Grants mai arziki sun ta'allaka ne a cikin gadaje yashi na Memba na Westwater Canyon da Member Jackpile. Ma'adinai a cikin wannan bel ya samar da  na U  O  tsakanin 1948 da 2002. Uranium ya hado ta hanyar tarkacen tsire-tsire da humate wanda ke aiki azaman masu ragewa. 

## Manazarta