Tsarin Tsarin Ajiye Kuɗin Mai Sanya Kuɗi
Ma'adinan da aka ajiye a wurin ajiya wani nau'in ma'adinan da aka samar ta hanyar tarin kayan aiki masu mahimmanci saboda ƙarfin da ke fitowa daga waje kamar su gurɓatawa, zaizayar ƙasa, sufuri, da kuma adanawa ta ruwa ko iska. Waɗannan ma'adinan galibi ana yin su ne don haƙar ma'adinai saboda suna iya ƙunsar ma'adanai masu daraja kamar zinariya, cassiterite (tin ma'adinai), zircon, rutile, ilmenite, monazite, har ma da duwatsu masu daraja. Babban halayyar ma'adinan da aka ajiye a wurin ajiya shine cewa ma'adanai masu nauyi suna taruwa a takamaiman wurare, waɗanda aka raba su da ma'adanai masu sauƙi waɗanda igiyoyin ruwa ke iya ɗauka cikin sauƙi.
Wannan labarin ya yi bayani dalla-dalla kan yadda ake samun ma'adinan placer, tun daga tushen dutse har zuwa samuwar manyan ma'adanai a cikin yanayin wurin ajiyar ma'adinai.
1. Tushen Ma'adinai da Duwatsu Masu Tushe
Tsarin samuwar ma'ajiyar wuri yana farawa ne da kasancewar duwatsun tushe masu ɗauke da ma'adanai masu mahimmanci. Misali, zinare galibi yana samo asali ne daga jijiyoyin hydrothermal quartz, cassiterite daga granite ko greisen, da kuma ma'adanai na yashi na ƙarfe (ilmenite-magnetite) daga duwatsun mafic da metamorphic igneous. Ana samun waɗannan duwatsun tushe a yankunan sama, tsaunuka, ko yankunan duwatsu da aka fallasa waɗanda daga baya suka fuskanci yanayi mai kyau.
Ma'adanai masu daraja a cikin dutsen iyaye galibi ana watsa su (ana yaɗa su) ko kuma a ɗaure su a cikin wasu tsare-tsare. Domin su zama wurin ajiye ma'adanai, dole ne a fara raba waɗannan ma'adanai da dutsen mai masaukin baki sannan a yi wa kansu rarrabawa ta halitta yayin jigilar su.
2. Tsaftacewa: 'Yantar da Ma'adanai Masu Muhimmanci
Lalacewar yanayi muhimmin mataki ne domin yana karya duwatsu kuma yana fitar da harakokin ma'adinai. Lalacewar yanayi na iya faruwa ta hanyoyi kamar haka:
– Yanayin yanayi na zahiri (na inji): duwatsu suna karyewa zuwa ƙananan gutsuttsura saboda canje-canje a yanayin zafi, daskarewar ruwa, ko aikin tectonic da nauyi.
– Mummunan yanayi na sinadarai: wasu ma'adanai suna narkewa ko canzawa zuwa sabbin ma'adanai kamar yumbu ta hanyar amfani da iskar shaka, ruwa, ko kuma carbonation.
– Yanayi na halitta: saiwoyin tsirrai da ƙananan halittu suna taimakawa wajen hanzarta rugujewar duwatsu.
Ma'adanai na Placer gabaɗaya suna da juriya ga yanayin sinadarai kuma suna da tauri da kwanciyar hankali mai yawa. Misali, zinari yana da ƙarfi sosai kuma ba ya amsawa; cassiterite shi ma yana da ƙarfi sosai. Saboda haka, yayin da sauran ma'adanai ke fuskantar canji da wargajewa, waɗannan ma'adanai masu nauyi suna kasancewa a matsayin hatsi marasa 'yanci.
3. Zaftarewar ƙasa da Sakin Kayan Aiki a Tsarin Sufuri
Bayan lalacewar dutse ta raunana, tsari na gaba shine zaizayar ƙasa, lalatawa da kuma cire kayan daga inda yake. Zaizayar ƙasa tana faruwa ne sakamakon kwararar ruwan sama, koguna, zaftarewar ƙasa, ko raƙuman ruwa da ke faɗuwa a bakin teku.
Kayan da aka saki za su shiga tsarin sufuri kamar koguna ko kwararar ruwa ta bakin teku. A wannan matakin, girman hatsi, siffar hatsi, da yawan ma'adanai za su yi tasiri sosai kan yadda ma'adanai ke motsawa. Wannan shine farkon rarrabawa ta halitta.
4. Sufuri: Matsayin Ruwa da Makamashin Ruwa
Yawancin ma'ajiyar placer ana samun ta ne ta hanyar jigilar ruwa, musamman koguna da tsarin bakin teku. A cikin kwararar ruwa, kayan sedimentary suna motsawa ta hanyoyi da dama:
– Dakatarwa: ƙananan ƙwayoyin da aka dakatar a cikin ruwa.
– Gishiri: ƙwayoyin yashi suna "tsalle" a kan gadon kogin.
– Ragewa: manyan hatsi ko masu nauyi suna birgima/jawo a ƙasan.
Ma'adanai masu nauyi kamar zinariya suna da yawan yawa (kimanin 19,3 g/cm³), wanda ya fi quartz (kimanin 2,65 g/cm³). Sakamakon haka, zinari yana iya zama cikin sauri kuma yana matsawa kusa da ƙasan rafin. A gefe guda kuma, ma'adanai masu sauƙi suna da sauƙin ɗauka a cikin daskararren wuri.
Duk da haka, sufuri ba wai kawai yana motsa abu ba ne; yana kuma "rarraba shi". Da zarar an kai ma'adinai da nisa, to, girman ƙwayarsa zai yi kyau kuma siffarsa za ta yi zagaye. Ana samun ƙwayoyin zinariya masu siffar ƙwallo a matsayin ƙuraje, ƙwayoyin da ba su da faɗi, ko ƙuraje, ya danganta da nisan da aka kai da kuma hanyar gogewa.
5. Rarrabawa da Tattara Ma'adanai Masu Girma
Ma'anar samuwar ma'ajiyar wuri shine yawan ma'adanai masu nauyi ta hanyar rarraba hydrodynamic. Tasirin yana faruwa ne saboda bambance-bambancen da ke cikin:
- Yawan yawa
- Girman hatsi da siffarsa
- Saurin kwarara da tashin hankali
Idan ƙarfin kwararar ruwa ya ragu—misali, a faɗaɗa sassan kogi, lanƙwasawa, a bayan duwatsu, ko kuma lokacin da ruwan ambaliyar ruwa ya fara raguwa—lalacewar ruwa mai nauyi za ta fi ta ƙasa da ƙasa mai sauƙi. Wannan tsari yana maimaita kansa, musamman a lokutan ambaliyar ruwa, wanda ke kawo sabbin kayayyaki da yawa, sai kuma lokacin zubar ruwa yayin da kwararar ruwa ke raguwa.
Sakamakon wannan maimaitawa, ma'adanai masu nauyi suna ƙara taruwa a wasu layuka, suna samar da "layin albashi" a cikin haƙar zinare mai alluvial: yadudduka masu arzikin zinare waɗanda galibi suna kusa da ƙasan laka, kusa da dutsen ko sama da wani yanki na tsakuwa mai kauri.
6. Muhalli na Ajiye Kuɗin Ajiya
Ma'ajiyar placer na iya samuwa a wurare daban-daban, kowannensu yana da nasa halaye:
a. Mai Sanya Kogi (Mai Sanya Ruwan Sama)
Wuraren da ake sanya ma'adanai a koguna su ne suka fi yawa. Wuraren da aka fi so don yawan ma'adanai sun haɗa da:
- Lanƙwasa kogin ciki (sandar maki)
- Fashewa da tsagewa a cikin dutsen da aka "kama" ma'adanai masu nauyi
– Yankin da ke bayan cikas kamar duwatsu
- Tsoffin baranda na koguna waɗanda ke rikodin hanyar tsoffin koguna
Rijiyoyin da ke kan baranda a koguna galibi suna da ƙarfi kuma ana iya amfani da su wajen haƙar ma'adinai masu yawa saboda ba koyaushe suke kusa da hanyoyin ruwa masu aiki ba.
b. Wurin Sanyaya Teku
A bakin teku, raƙuman ruwa da raƙuman ruwa masu tsayi suna rarraba laka sosai. Ma'adanai masu nauyi kamar ilmenite, rutile, zircon, da monazite galibi suna taruwa cikin "yashi baƙi." Raƙuman ruwa da kwararar ruwa masu maimaitawa suna wanke laka mai sauƙi zuwa teku, yayin da ma'adanai masu nauyi ke wanzuwa kuma suna taruwa.
c. Mai Sanya Teku Mai Rufi (Mai Sanya Teku)
Wasu wuraren da aka sanya su suna samo asali ne daga bakin teku ko kayan kogi waɗanda aka ajiye a kan ƙananan ɗakunan ruwa. Raƙuman ruwa, raƙuman ruwa, da guguwa suna aiki a matsayin abubuwan da za su iya rarrabawa waɗanda za su iya samar da manyan ma'adanai a ƙasan teku.
d. Mai Sanya Iska (Mai Sanya Eolian)
Duk da cewa iska ba ta cika faruwa ba, iska na iya samar da wuraren da za a iya sanyawa a wuraren hamada ko rairayin bakin teku masu yashi. Iska tana saurin motsa ƙananan hatsi cikin sauƙi, tana barin ma'adanai masu nauyi a baya a matsayin wuraren da ake samun raguwar ruwa.
7. Matsayin Tarkuna na Halitta a cikin Tattara Placer
Domin ƙirƙirar ma'adanai masu tarin ma'adanai, ana buƙatar tarkuna don hana ma'adanai masu nauyi su tafi da su ta hanyar kwararar ruwa. Waɗannan tarkuna na iya haɗawa da:
- Tsarin bene mara daidaito (ƙananan ramuka, tsagewa, ko matakai)
- Wani yanki na tsakuwa mai kauri wanda ke aiki kamar "sieve"
- Tsarin sedimentary kamar ripples, giciye-bedbeds, ko sanduna
- Tsire-tsire da shingayen halitta waɗanda ke rage kwararar ruwa
Misali, zinare yakan taru a cikin zurfin sassan laka saboda nauyinsa yana sa ya "nutse" tsakanin tsakuwa ya isa ga dutsen. Saboda haka, haƙar ma'adinai sau da yawa yakan kai hari ga ƙananan layukan.
8. Binnewa, Takaitawa, da kuma Samar da Ƙarin Kuɗi na Dindindin
Bayan lokaci, za a iya rufe ma'ajiyar placer da sabbin laka, a taƙaice su, sannan su girma a fannin ilimin ƙasa. A tsawon lokaci, canjin koguna ko canje-canje a matakin teku na iya ɗaga ma'ajiyar zuwa baranda ko kuma su nutsar da su cikin yanayin ruwa.
Duk da cewa ma'ajiyar placer gabaɗaya ba ta fuskantar babban lithification kamar tsoffin ma'ajiyar sedimentary, wasu tsoffin ma'ajiyar placer na iya zama conglomerates. Misalin da ake yawan tattaunawa a fannin ilimin ƙasa shine conglomerates masu arzikin zinare a cikin tsoffin tsarin sedimentary, waɗanda ke yin rikodin irin wannan tsari, wanda ke faruwa ne kawai a cikin tarihin ƙasa mai nisa.
Kammalawa
Samuwar ma'ajiyar placer sakamakon dogon jerin abubuwan da suka faru na sake faruwa na duwatsun tushe, zaizayar ƙasa, sufuri, rarrabawa, da kuma adanawa. Babban abin da ke cikin darajar tattalin arzikin masu sanya placer shine ikon yanayi na tattara ma'adanai masu nauyi, masu jurewa - kamar zinariya, cassiterite, da ma'adanai masu nauyi - a takamaiman wurare waɗanda ke aiki a matsayin tarkon laka. Koguna, yankunan bakin teku, da kuma yanayin ruwa mara zurfi suna samar da yanayin kuzari mai ƙarfi wanda ke ba da damar yawan ma'adanai ya faru ta halitta.
Ta hanyar fahimtar waɗannan hanyoyin, masana kimiyyar ƙasa da masu hakar ma'adinai za su iya hango wurin da za a ajiye ma'ajiyar mai, su tantance ingancin ma'ajiyar, da kuma tsara hanyoyin bincike da haƙar ma'adinai mafi inganci da kuma alhakin muhalli.
