Ib tug ze li ntawm 3-bn vam-xyoo-laus banded hlau tsim los ntawm Canada qhia tias huab cua thiab dej hiav txwv ib zaug tsis muaj oxygen. Cov kab mob Photosynthetic tau ua oxygen, tab sis nws tau hnov mob nrog cov hlau yaj hauv dej hiav txwv los tsim cov hlau oxide cov zaub mov hauv dej hiav txwv, tsim cov hlau nplaum.
Thaum twg cov hlau nplaum tsim tawm?
Banded Hlau Tsim. Banded Iron formations tshwm sim hauv cov pob zeb Proterozoic, xws li hnub nyoog ntawm 1.8 txog 2.5 billion xyoo. Lawv yog tsim los ntawm alternating txheej ntawm hlau-nplua nuj khoom (feem ntau magnetite) thiab silica (chert).
Banded hlau tsim hauv kev tshawb fawb yog dab tsi?
Banded hlau-formations yog sedimentary pob zeb formations nrog alternating silica-nplua txheej txheej thiab hlau-nplua nuj txheejuas feem ntau muaj li ntawm hlau oxides (hematite thiab magnetite), hlau nplua nuj carbonates (siderite thiab ankerite), thiab / lossis hlau nplua nuj silicates (e.g., minnesotaite thiab greenalite).
Banded hlau yog dab tsi?
Feem ntau ntawm cov hlau loj thoob ntiaj teb tshwm sim hauv cov pob zeb hu ua banded hlau formations (los yog BIFs luv luv), uas yog cov pob zeb zoo li txheej sedimentary tsim los ntawm alternating chert (ib daim ntawv ntawm quartz) thiab hlau oxide. bands.
Vim li cas cov hlau thaiv hlau nres nres?
3. Kev tsim ntawm ntau BIFs tau nres ib zaug feem ntau ntawm cov hlau los ntawm dej hiav txwv tau siv uas ua rau tsim cov pa hauv huab cua raws li tau hais los ntawm thawj qhov tshwm sim ntawm cov txaj liab continental ntawm lub post- BIF Earth.
