Geology na yankin Bryce Canyon

Fannin yanayin ƙasa na yankin Bryce Canyon a Utah yana nuna rikodin ajiya wanda ya ƙunshi ɓangaren ƙarshe na Lokacin Cretaceous da rabin farkon zamanin Cenozoic a wannan yanki na Arewacin Amurka . Tsohuwar yanayin depositional na yankin da ke kusa da wurin da ake kira Bryce Canyon National Park ya bambanta da zurfin teku mara zurfi (wanda ake kira Cretaceous Seaway ) wanda aka ajiye Dakota Sandstone da Tropic Shale zuwa rafukan sanyi da tafkuna waɗanda ke ba da gudummawar laka zuwa Tsarin Claron mai ban sha'awa wanda ya mamaye wuraren shakatawa na amphitheaters.

An kuma samar da wasu nau'o'in amma galibi an lalata su ne biyo bayan tashi daga Laramide orogeny wanda ya fara kusan 70. shekaru miliyan da suka wuce ( Mya ). Wannan taron ya tayar da tsaunin Rocky da nisa zuwa gabas kuma ya haifar da ja da baya na tekun da ya rufe yankin Bryce Canyon. Bayan ginin dutsen Laramide ya ƙare, kusan 15 mya, wani babban yanki na yammacin Arewacin Amurka ya fara shimfiɗawa zuwa cikin Basin da ke kusa da yanayin yanayin Range . An ɗaga yankin Bryce mafi girma a matsayin wani ɓangare na Babban Plateaus da runduna iri ɗaya. Haɓakawa na Colorado Plateaus da buɗe Gulf of California ta 5 mya ya canza magudanar ruwa na Kogin Colorado da magudanan ruwa, gami da kogin Paria, wanda ke kan gaba tsakanin tudu biyu da ke kusa da wurin shakatawa. Wannan ɗagawa ya haifar da samuwar haɗin gwiwa a tsaye wanda daga baya aka fi so ya ɓata don samar da ƙwanƙolin yanci da ake kira hoodoos, badlands, da monoliths da muke gani a yau.

Siffofin da aka fallasa a yankin wurin shakatawa wani yanki ne na Babban Matakai . Tsofaffin mambobi na wannan babban jerin raka'o'in dutse an fallasa su a cikin Grand Canyon, masu matsakaici a cikin Sihiyona National Park, kuma mafi ƙanƙanta sassa an shimfiɗa su a cikin yankin Bryce Canyon. Ƙananan adadin zoba yana faruwa a ciki da kewayen kowane wurin shakatawa.

 Grand Staircase 

alt=Cross section diagram of rock layers|thumb|250x250px|Grand Canyon (A), Chocolate Cliffs (B), Vermilion Cliffs (C), White Cliffs (D), Canyon Canyon (E), Grey Cliffs (F), Pink Cliffs (G), Bryce Canyon (H)
Babban Staircase jerin jeri ne na dutsen dutse, wanda aka fara bayyana a cikin 1870s, wanda ya shimfiɗa kudu tsawon  daga Bryce Canyon National Park ta hanyar Sihiyona National Park zuwa cikin Grand Canyon .  Bryce Canyon yana cikin tsaunin ruwan hoda, mafi girma kuma mafi ƙanƙanta a cikin babban bene.  

 Cretaceous Seaway 
A cikin Cretaceous, wata hanyar ruwa mara zurfi ta bazu zuwa cikin Arewacin Amurka daga Gulf of Mexico a kudu zuwa Utah sannan daga baya zuwa Tekun Arctic a arewa mai nisa.  Masana ilmin ƙasa suna kiran wannan teku mai zurfi da Cretaceous Seaway ko Yammacin ciki na Yammacin Turai. Hanyar teku ta raba Arewacin Amurka gida biyu: wani yanki na gabas wanda tsohon tsaunukan Appalachian ya mamaye da kuma wani yanki na yamma wanda ya ƙunshi babban tsaunin Sevier;  ya samo asali ne daga kuskuren matsawa mai zurfi wanda Sevier orogeny ya haifar.  Yayin da bakin tekun ke motsawa baya da gaba, yankin Bryce ya canza daga zama wani ɓangare na Sevier landmass zuwa kasancewa ƙarƙashin Tekun Cretaceous. Matsalolin da ba na ruwa ba, intertidal, da na ruwa sun kwanta a saman juna sakamakon haka.

Ƙwararren dutse, siltstone, da dutsen yashi mai arzikin burbushi waɗanda tare sun kai  mai kauri alama zuwa na Cretaceous Seaway.  Da ake kira Dakota Sandstone, shine mafi tsufa samuwar da aka fallasa a yankin Bryce Canyon amma ƙaramin wanda aka fallasa a yankin Sihiyona da Kolob canyons zuwa kudu maso yamma. Yawan itace mai yawa, gadaje kawa mai dauke da miliyoyin burbushin halittu, da gawayi duk ana samunsu a Dakota.  A cikin yankin Bryce Canyon, ana iya ganin wannan samuwar a cikin kwarin Paria inda aka samo shi azaman yashi bargo wanda mai yiwuwa ya taru a kan rairayin bakin teku, a cikin lagoons, da gulman da ke samar da kwal yayin da Cretaceous Seaway ya keta (ci gaba a cikin ƙasa) a kan yankin kuma daga baya ya koma baya.  Yana zaune ba daidai ba a kan tsofaffin tsarin Jurassic waɗanda ba a fallasa su a cikin yankin nan da nan (duba ilimin geology na yankin Sihiyona da Kolob don tattaunawa game da waɗannan tsofaffin sediments).

An ajiye laka da silt a saman Tsarin Dakota yayin da tekun ya zama zurfi da kwanciyar hankali a yankin.  Sakamakon launin toka mai duhu zuwa baƙar fata Tropic Shale yana rubuta iyakar iyakacin iyaka na hanyar teku zuwa Utah kuma yana da  kauri a cikin Paria Amphitheater.  Yana samar da ciyayi maras ciyawa da aka gani a cikin kwarin Tropic kuma watakila shine mafi kyawun burbushin halittu a yankin; yana dauke da ammonawa masu harsashi da yawa madaidaiciya. 

 Ja da baya 
Tekun Cretaceous ya riga ya ja da baya gabas da kudu a lokacin da yankin ya  An ajiye Ƙirƙirar Dutsen Madaidaici mai kauri.  Membobinta suna wakiltar matakai daban-daban a cikin wannan tsari. Dutsen dutse mai yashi na Memba na Tibbet Canyon an ajiye shi yadda ya kamata a saman tsaunin Tropic Shale a cikin ruwa mara zurfi kuma daga baya kusa da yanayin gaɓa. Shale da dutsen yashi daga Memba na Smoky Hollow an ajiye su a saman babban dutsen laka mai arzikin gawayi a cikin fadama na bakin teku da kuma lagoons a bakin tekun. Yayin da madaidaicin yadudduka na shale da dutsen yashi gauraye da dumbin ma'adinan gawayi na John Henry Memba an shimfida su a cikin fadama, lagos da muhallin ruwa, ba a samun memba daya, Drip Tank, a yankin Bryce Canyon.  Wannan samuwar tana lalata kusan tsaunin da ba za a iya hawa ba da kuma ɓangarorin fararen fararen fararen duwatsu masu launin rawaya- launin toka tare da kwatankwacin siraran siraran da ke tsaka-tsaki na shale da dutsen laka. Ana samun hakoran shark a cikin ƙananan sassa na samuwar. 

Tafkuna da koguna masu gudana daga gabas sun zama babban wurin hutawa don laka bayan ja da baya na Tekun Cretaceous. Shales da dutsen sandstone na gida  An ajiye Tsarin Wahweap mai kauri a cikin ruwa mai motsi (tsarin ruwa).  Wannan samuwar wani bangare ne na Grey Cliffs na Babban Matakan da aka ambata a baya. Ya ƙunshi dumbin burbushin kashin baya, gami da dinosaurs kamar hadrosaurs . 

 Jigilar Continental 

 Filayen ambaliya suna ɗagawa da lalacewa 
alt=Tall pink-colored rock formations|thumb|Hoodoos a cikin Tsarin Claron, Bryce Canyon
Wani filin ambaliya da ya ratsa ta koguna da tafkuna ya taso a yankin. Laka da yashi sun taru a wannan wuri don zama dutsen yashi mai launin toka da duwatsun laka na Kaiparowits Formation . Wannan tsari ya kai  mai kauri a cikin yankin Bryce Canyon, amma sauran sassan Kaiparowits a yankin suna da kauri da yawa na ɗarurruwan ƙafa (mita goma).  Tsarin guda biyu, Kan'ana Peak da Pine Hollow, suna zaune a saman Kaiparowits a wani wuri a cikin yankin amma ba sa nan a yankin Bryce Canyon. Duwatsun yashi da tarkace na waɗannan gyare-gyare suna yin rikodin rafi da jigon kogin da suka fara a zamanin Paleocene . 

Ɗaukakawa da aka yi ta hanyar ginin dutse mai suna Laramide orogeny ya dade daga marigayi Cretaceous kusan 70. mya zuwa farkon Paleocene. Wannan ya ɗaga saman ƙasan sama a baya yayin da ƙwanƙolin kwandon shara a tsakanin su ya ragu a hankali.  Matsi daga taron Laramide ya lalata ƙasa a yankin don samar da har zuwa 5 ° dipping Bryce Canyon Anticine. Dukkanin Tsarin Kan'ana Peak, Pine Hollow, Kaiparowits, da Waheap, tare da wani yanki na Madaidaicin Dutsen Madaidaici, an cire su daga ɓangarorin ɓarke ta hanyar lalacewa kafin a ajiye Tsarin Claron.  Saboda haka rashin daidaituwa na kusurwa yana wanzu tare da ƙwanƙolin antiline. Wurin shakatawa kuma yana zaune a gefen yamma a hankali yana nutsewa a gefen babban Kaibab wanda ya fi girma, wanda kuma ya kasance sakamakon Laramide. 

 Claron ambaliya fili da tsarin tafkin 
An dakatad da ɗagawa daga Laramide na ɗan lokaci a cikin Eocene .  Rafukan ma'ana suna gudana a hankali a kan faɗuwar faɗuwar faɗuwar kuma kusan marasa fasali. Ambaliyar ruwa ta lokaci-lokaci amma ta mamaye manyan yankuna watakila sau ɗaya a kowace shekara 1,000; yana yada laka, tarkace da lallausan sitti a kan filayen.  Zazzagewa ya haifar da waɗannan adibas tsakanin abubuwan da suka faru na ambaliya da tsiron tsiro yana da yawa. Oxidation na baƙin ƙarfe a cikin laka da silt ya mayar da ƙasa zuwa hematite, yana ba ta ruwan hoda da ja. Daga baya an lithified waɗannan sediments zuwa cikin sama-zuwa  -kauri Pink Memba na gida Eocene-shekaru Claron Formation (wanda ake kira da Wasatch Formation).  Ana iya ganin ƙungiyoyin da aka ba da izinin wannan memba cikin sauƙi a cikin Red Canyon tare da Hanyar Jiha 12 yayin da silt da duwatsun laka ke tsara yawancin wuraren shakatawa masu rauni da launuka masu launi da ake kira hoodoos . Masanin ilimin ƙasa Clarence Dutton da ake kira iron oxide -rich ƙananan memba na jerin Claron the Pink Cliffs saboda kamanninsa. 
alt=Brown map with a large lake on it|right|frame|Tsarin tafkin Claron
Babban tsarin tafkuna mara zurfi amma faffadan tafkuna da kuma haɗe- haɗe sun rufe mil mil dubu da yawa na abin da ke arewa maso yammacin Colorado da kudu maso yamma Utah da Wyoming .  Waɗannan tafkuna sun kasance daga Paleocene zuwa tsakiyar Oligocene amma ba su bazu zuwa yankin Bryce Canyon ba har sai lokacin Eocene.  An shimfida adadi mai yawa na lakebed a cikin wannan tsarin a cikin shekaru miliyan 20 na wanzuwarsa daga kusan 60 zuwa 40. mya.  Sauyin yanayi da hawan keke ya haifar da tafkunan da ke cikin tsarin don fadadawa da raguwa ta lokaci. Suna yin haka, sai suka bar gadaje masu kauri dabam-dabam da abubuwan da ke tattare da juna. 

 yashi daban-daban da ma'auni a kusa da bakin teku,
 alli - matalauta laka gaba daga tudu;
 laka mai arzikin calcium a cikin ruwa mai zurfi, da
 An zuba ruwan lemun tsami zalla a cikin ruwa mafi zurfi.

Daga baya an zuba lemun tsami da laka a cikin dutsen farar ƙasa da dutsen siltstone na sama da 300. kafa (90 m) - Farin Memba na Claron.  Wannan memba yana ɓarna zuwa cikin farar fata masu launin monoliths waɗanda aka samo su kawai a mafi girman tudu na Paunsaugunt Plateau . Burbushin halittu ba safai ba ne a cikin Farin Memba kuma sun ƙunshi galibin katantanwa na ruwa mai daɗi da ƙugiya, wanda ke nuna cewa tabkuna suna tallafawa ƙaramin rayuwa.  Yawancin arches da gadoji na halitta a cikin wurin shakatawa, gami da sanannen gadar Halitta, an zana su daga gadaje na yashi a cikin Claron.

 Marysvale volcanics 
An katse rata a cikin rikodin geologic bayan ƙaddamar da Tsarin Claron 34 zuwa 31 mya ta fashewa daga filin wuta na Marysvale na kusa, wanda ke arewa maso yammacin wurin shakatawa.   Ana samun tokar wuta da lava daga waɗannan magudanar ruwa ƙasa da  daga Bryce Canyon amma aƙalla wasu abubuwa masu aman wuta ana iya ajiye su kai tsaye a cikin wurin shakatawa kawai daga baya zazzagewa za a cire su. 

Yawancin ayyukan da ake yi a filin volcanic na Marysvale sun faru ne a cikin tazara guda uku; – ina, – ina da – mya. Cunningham, Charles G. (2002).  Dacites da andesites sun fashe a saman wani baholith mai tasowa a cikin tazara ta farko. Toka mai arzikin Crystal daga mai shekaru miliyan 27 (myo) Three Creeks caldera, 24 myo Big John caldera da 23 myo Monroe Peak caldera ya taurare cikin tuff .  Tazara na biyu da na uku sun ga fashewar rhyolite masu yawa. Alkali -rich rhyolite ya fashe a tazara na biyu daga 19 myo Mount Belknap caldera. 

Filin dutsen mai aman wuta na Marysvale ya ruguje karkashin nauyinsa kusan 20 mya; mai yiyuwa ne saboda raunin da aka samu a cikin ɓangarorin Tsarin Karmel kusan  kasa.  Nadawa da kuskuren Tsarin Claron daga rugujewar ya haifar da tura Ruby's Inn. An kuma ƙirƙiri ɗan ƙaramin faɗuwar ƙasa da ke gudana gabas – yamma da kuma daidai da motsin motsi da ake kira Bryce syncline.  Ayyukan Volcanic a cikin Marysvale da Bryce yankin ya ƙare kimanin shekaru 500,000 da suka wuce.  Ana iya ganin duwatsun Basaltic na zamani guda tare da Sevier Fault kusa da ƙofar Red Canyon; Duwatsun tsaunukan tsaunuka masu duhun wuta sun yi gudun hijira saboda laifin kusan  kuma yanzu suna cikin hulɗa kai tsaye tare da mafi tsufa Claron Formation. 

 Late Cenozoic tectonics 

 Samuwar Babban Plateaus 
alt=Raised map|right|frame|Colorado Plateau taswira
Ƙananan rukunin dutsen an shimfiɗa su amma galibi an cire su ta hanyar haɓaka haɓakar yazawar da ta biyo baya. Ana iya samun ɓangarorin waɗannan ƙera a yankin arewacin wurin shakatawa da kuma a wasu wurare kaɗan a kan tudu. Daga cikin waɗannan akwai  Oligocene mai kauri ko Miocene mai shekaru Boat Mesa Conglomerate da Pliocene zuwa farkon Pleistocene mai shekaru Sevier River Formation .  Boat Mesa an yi shi ne mafi yawan ƙungiyoyin haɗin gwiwa tare da ƙananan dutsen yashi da wasu dutsen farar ƙasa daga tafkuna, wakiltar rafi da ajiyar ambaliyar ruwa.  Yashi mai launin ruwan toka-launin toka da tsakuwa na Tsarin Kogin Sevier an shimfiɗa su a cikin kwaruruka waɗanda ke cikin tsarin magudanar ruwa na Sevier River kakanni.  

Kusan 15 mya a lokacin Miocene, sojojin tashin hankali a Nevada zuwa yamma sun yi girma sosai har ɓawon burodi ya bazu cikin bakin ciki, yana haifar da Lardin Basin da Range .  Waɗannan runduna guda ɗaya sun raba abin da ke yammacin yankin Colorado Plateau zuwa ƙananan faranti tara daban-daban, gami da Paunsaugunt wanda wurin shakatawa ke zaune.   Dogayen, arewa-kudu- matsalolin al'ada na yau da kullun an ƙirƙira su ko kuma an sake kunna su daga tsofaffin kurakuran da suka gabata; wani tudu ya tashi a gefe ɗaya na kowane laifi yayin da kwaruruka suka ragu a ɗayan yayin da aka shimfiɗa ɓawon burodi a gabas zuwa yamma.  Biyu daga cikin waɗannan kurakuran sun ɗaure Plateau Paunsaugunt; Sevier a yamma da Paunsaugunt a gabas. Motsawa tare da waɗannan kurakuran guda biyu ya raba Tsarin Claron da 2,000 ƙafa (600 m) dangi zuwa kwarin Paria da Sevier. 

Lalacewar guguwar ta yi nuni da gefen yamma na Markagunt Plateau kuma ita ce kan iyaka tsakanin Basin da Range da lardunan Plateaus na Colorado.  Cedar Breaks National Monument, wanda ke da alaƙa kusan iri ɗaya da aka fallasa yanayin ƙasa da sifofin ɓarna kamar Bryce Canyon National Park, yana zaune a gefen yamma na Markagunt.

Gaba dayan Plateau na Colorado daga nan ya fara tashi daga kusa da matakin teku zuwa ƙafa dubu da yawa (fiye da kilomita ɗaya) a tsayi.  Wata ka'ida ta daban ita ce, Laramide orogeny ya ɗaga abin da yake a yau Basin da Range da Colorado Plateau da kuma cewa dakarun tashin hankali da suka kafa Basin da Range sun sa wannan yanki ya ragu dangane da Colorado Plateau.  Ko menene tsarin abubuwan da suka faru, yankin High Plateaus na Colorado Plateau ya kusan kammala.

 Magudanar ruwa na zamani da zaizayar kasa 
Magudanar ruwa na Plateau na Colorado ya sami canji sosai ta hanyar buɗe Gulf of California . Rifting ya tsaga Baja California Peninsula zuwa arewa maso yamma daga babban yankin Mexico wanda ya fara kusan 10 zuwa 5 mya.  Kogin Colorado na kakanni ya mayar da martani ga raguwar yanki ta hanyar ɗaukar gajeren hanya zuwa teku ta hanyar shiga cikin sabon gulf. Hakan ya rage nisa sosai daga magudanar ruwan kogin da kuma tudun sa a tekun. Ruwa a cikin Colorado da magudanan ruwa ya yi sauri a sakamakon haka kuma ya yanke zurfi, ya haifar da zane-zane na canyonland.

Samar da kusan zurfin zurfin Kogin Colorado na Grand Canyon da 1.2 mya ya kara haifar da raguwar magudanan ruwa har ma da zurfi.  Rushewar kai na ɗaya daga cikin waɗancan ƙorafin, Kogin Paria, ya ɓata arewa-arewa maso yamma zuwa abin da ake kira Paria Amphitheater a yanzu.  Kogin ya ɗauki hanya mai madaidaici zuwa da gabas na Laifin Paunsaugunt. Yazara daga dusar ƙanƙara da ruwan sama waɗanda ke faɗo kai tsaye a gefen gabas da ke fuskantar Paunsaugunt Plateau ya haifar da gullies waɗanda ke faɗaɗa cikin alcoves da amphitheater yayin da bambance-bambancen yashwar da sanyin sanyi ke haifar da hoodoos . Rafukan da ke kan tudu ba sa taimakawa wajen samar da alcoves ko amphitheater saboda suna gudana daga bakin.  Zazzagewa yana ci gaba a cikin wannan salon a yau.

 Ƙirƙirar Hoodoo a cikin Bryce Canyon 
alt=Sequence showing progressively eroded rocks|right|Samuwar Hoodoo
Memba mai ruwan hoda na Claron Formation ya ƙunshi mafi yawa daga cikin sassauƙan ruɓewa da ɗan ƙaramin dutse mai laushi. Lokacin da ruwan sama ya haɗu tare da carbon dioxide yana samar da wani bayani mai rauni na carbonic acid . Wannan acid yana taimakawa sannu a hankali narkar da farar ƙasa a cikin ƙwayar Claron Formation ta hatsi. Wannan tsari na yanayi na sinadarai ne ke zagaye gefen hoodoos kuma yana ba su ƙullun bayanansu.

A cikin hunturu, dusar ƙanƙara mai narkewa tana shiga cikin tsagewa da haɗin gwiwa kuma yana daskarewa da dare. Ƙarfin ƙanƙara mai faɗaɗa yana taimakawa wajen lalata dutsen Ƙarfafawar Claron. Fiye da 200 na waɗannan daskarewa/narkewa suna faruwa kowace shekara a Bryce Canyon.  Frost wedging yana amfani kuma yana faɗaɗa jiragen haɗin gwiwa kusan tsaye waɗanda ke rarraba Memba na Pink na Tsarin Claron.

Yadudduka na ciki na dutsen laka, conglomerate da siltstone suna katse farar ƙasa a kwance. Waɗannan yadudduka sun fi jure wa harin carbonic acid don haka suna iya yin aiki azaman dutsen kariya na fis, tagogi da hoodoos. Yawancin hoodoos masu ɗorewa suna lulluɓe da nau'in dutse mai arzikin magnesium da ake kira dolomite . "Hoodoos".  Dolomite yana narkewa a hankali a hankali, kuma saboda haka yana kare ƙarancin farar ƙasa a ƙasa.

Koyaya, hanyoyin guda ɗaya waɗanda ke haifar da hoodoos suma zasu lalata su a ƙarshe. A cikin yanayin Bryce Canyon, ƙimar hoodoos na yashwa shine 2 – 4 ƙafa (0.6 – 1.3 m) kowace shekara 100.  Yayin da kogin ya ci gaba da raguwa zuwa yamma zai iya kama (a cikin watakila shekaru miliyan 3) magudanar ruwa na Gabashin Fork na Kogin Sevier . Da zarar wannan kogin ya ratsa ta Bryce Amphitheater zai mamaye tsarin lalata; maye gurbin hoodoos tare da rafi mai siffar V da ganuwar dutse mai tsayi irin na yanayin yanayi da yaɗuwar yanayin da koguna suka yi. Ana iya ganin kwatankwacin wannan a cikin Ruwan Ruwa yayin tafiya Titin Mossy Cave Trail. Canal diversion da ake kira Tropic Ditch ya kwashe shekaru sama da 100 yana shan ruwa daga Gabashin Fork na Kogin Sevier ta wannan sashin shakatawa. 

 Manazarta 

Rukuni:Shafuka masu fassarorin da ba'a duba ba