Hogback (geology)

A cikin ilimin ƙasa da ilimin ƙasa, **[[Aladu|hog]]** ko bayan alade tsawo ne, kunkuntar tudu ko jerin tuddai tare da kunkuntar tuddai da gangara masu tsayi kusan daidaito a bangarorin biyu. Yawanci, kalmar ta ƙuntata ga tudun da aka kirkira ta hanyar bambancin lalacewar fitowa, nutsewa sosai (fiye da 30-40 °), homoclinal, kuma yawanci sassan sedimentary. Ɗaya daga cikin gefen hogback (baya) ya ƙunshi farfajiyar (jirgi na gado) na dutse mai zurfi da ake kira tudun. Sauran gefen (tsarinsa, frontslope ko "ƙananan gangara") fuskar lalacewa ce da ke yankewa ta cikin ɓangarorin nutsewa waɗanda suka haɗa da hogback. Sunan "hogback" ya fito ne daga Hog's Back of the North Downs a Surrey, Ingila, wanda ke nufin kamanceceniyar yanayin ƙasa a cikin tsari zuwa bayan alade. Ana amfani da kalmar a wasu lokuta ga drumlins kuma, a Maine, ga duka eskers da ridges da aka sani da "horsebacks".

Hogbacks wani nau'i ne na yanki na yanki na ƙwayoyin ƙwayoyin da ke nutsewa, yawanci ƙwayoyin ruwa, waɗanda suka ƙunshi gadaje masu sauyawa na ƙwayoyi masu wuya, ƙwayoyin dutse da dutse, kuma ko dai raunana ko ƙwayoyin siminti, watau shale, mudstone, da marl. Yankin wani nau'i mai wuya, mai tsayayya da lalacewa ya zama gangaren baya (dip-slope) na hogback inda aka fi cire ƙananan abubuwa daga ciki ta hanyar lalacewa. Kayan da ke gaba da shi wanda ke samar da gaban hogback, wanda shine tsaunuka ko tsaunuka, ya ƙunshi gangara wanda ke yankewa a fadin gado shimfidar. Saboda yanayin da ke nutsewa sosai na sassan da ke samar da hogback, ɗan canji a wuri na iya faruwa yayin da yanayin ya ragu ta hanyar rushewa, amma zai zama batun ƙafa maimakon mil, kamar yadda zai iya faruwa da cuestas.

Dukkanin gradations suna faruwa tsakanin hogbacks, homoclinal ridges, da cuestas. Bambance-bambance tsakanin waɗannan siffofin ƙasa suna da alaƙa da tsananin nutsewar gadaje masu tsayayya waɗanda aka rushe su da kuma girman su. Inda kowane nau'in ya faru ya dogara da ko halayen dutse na gida ko dai kusan tsaye ne, matsakaici nutsewa, ko nutsewa a hankali. Saboda yanayin su na gradational, ainihin kusurwar nutsewa da gangara wanda ke raba waɗannan siffofin ƙasa ba daidai ba ne kuma wasu bambance-bambance a cikin takamaiman kusurwoyin da aka yi amfani da su don bayyana waɗannan siffofin ƙasar ana iya samun su a cikin wallafe-wallafen kimiyya. Hakanan yana iya zama da wahala a rarrabe membobin da ke kusa da wannan jerin siffofin ƙasa.

## Misalan

### Turai

#### Ƙasar Ingila

* Hog's Back, na Arewa Downs a Surrey, Ingila; asalin hogback daga inda yanayin ya samo sunansa. An kafa shi ne daga wani nau'i mai laushi, wanda ke haifar da gadaje masu laushi waɗanda suka fi tsayayya da rushewa fiye da yumbu mai laushi.

#### Belgium

* Richelsley a yammacin Arewacin Eifel, Belgium.

#### Jamus

* Teufelsmauer ("Ganuwar Iblis") a arewacin Harz Foreland .
* Externsteine a cikin dazuzzukan Teutoburg .
* Ith, wani dutse mai iyaka a cikin Weser Uplands.

### Arewacin Amurka

#### Colorado

Dinosaur Ridge sanannen hogback ne wanda yake wani ɓangare na Morrison Fossil Area National Natural Landmark a cikin Morrison, Colorado . Yana da hogback wanda aka kafa ta hanyar bambancin lalacewar sandstones masu kyau na Cretaceous Dakota Formation, wanda ke samar da gangaren ruwa na wannan hogback, wanda ke rufe ƙananan masu tsayayya da lalacewa da kuma laka mai laushi, siltstone, da ƙananan sandstones na Morrison Formation na zamanin Jurassic. Dinosaur Ridge wani ɗan gajeren ɓangaren Dakota Hogback ne wanda ya faɗaɗa tsawon Front Range daga Wyoming zuwa kudancin Colorado.

Grand Hogback yana da tsawon kilomita 70 (kilomita 110) wanda ke yammacin Colorado. Yana nuna wani ɓangare na iyaka tsakanin Colorado Plateau zuwa yamma da Kudancin Rocky Mountains zuwa gabas.

#### Black Hills
Duk da yake mafi yawan hogbacks suna tafiya tare da farfajiyar a cikin layi mai laushi, wasu, kamar waɗanda ke Wyoming" id="mwlw" rel="mw:WikiLink" title="Sundance, Wyoming">Sundance, Wyoming, suna kewaye da dome. Dakota Sandstone Hogback ya kewaye Black Hills, wani dome mai laushi wanda ya kai daga arewa maso yamma Dakota ta tudun zuwa arewa maso gabas Wyoming. Black Hills suna da kimanin kilomita 125 (201  tsawo da kilomita 65 (105  fadi. Dutsen Dakota Hogback ya samo asali ne lokacin da aka ɗaga sandstones masu tsayayya na Dakota Sandstone da ƙananan ɓangarorin da ke kusa da tsakiyar Black Hills na yanzu saboda shiga dutse, kimanin shekaru miliyan 60 da suka gabata. Black Hills sune ɓangaren gabashin Laramide orogeny. Yankin Dakota hogback ya raba filayen da ke kewaye da shi daga rami mai faɗin kilomita biyu (3.2) Red Valley na Black Hills. Dutsen "yana da fuska mai tsawo zuwa kwarin kuma ya tashi da yawa daruruwan ƙafa sama da shi.

Green Mountain, wanda aka fi sani da Little Sundance Dome, ana samunsa a gabashin Sundance, Wyoming. Yana da wani zagaye dome game da   a fadin da   fadi kewaye da wani rim na triangular hogbacks (kamar yadda a bayyanar flatirons). Green Mountain kanta, kamar Black Hills da ke kusa, laccolith ne wanda aka kafa ta hanyar shiga Magma a cikin ɓawon burodi na Duniya.

## Manazarta