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  2. Iron (II) carbonate - Wikipedia

    en.wikipedia.org/wiki/Iron(II)_carbonate

    Iron(II) carbonate, or ferrous carbonate, is a chemical compound with formula FeCO 3 , that occurs naturally as the mineral siderite . At ordinary ambient temperatures, it is a green-brown ionic solid consisting of iron(II) cations Fe 2+

  3. Siderite - Wikipedia

    en.wikipedia.org/wiki/Siderite

    Siderite is a mineral composed of iron(II) carbonate (FeCO 3). Its name comes from the Ancient Greek word σίδηρος (sídēros), meaning "iron". A valuable iron ore, it consists of 48% iron and lacks sulfur and phosphorus.

  4. Concretion - Wikipedia

    en.wikipedia.org/wiki/Concretion

    When the iron-bearing groundwater came into contact with more oxygen-rich groundwater, the reduced iron was converted back to insoluble iron oxide, which formed the concretions. [74] [75] [76] It is possible that reduced iron first formed siderite concretions that were subsequently oxidized. Iron-oxidizing bacteria may have played a role. [77]

  5. Green rust - Wikipedia

    en.wikipedia.org/wiki/Green_rust

    Green rust is a generic name for various green crystalline chemical compounds containing iron(II) and iron(III) cations, the hydroxide (OH −) anion, and another anion such as carbonate (CO 2− 3), chloride (Cl −), or sulfate (SO 2− 4), in a layered double hydroxide (LDH) structure. The most studied varieties are the following: [1]

  6. Banded iron formation - Wikipedia

    en.wikipedia.org/wiki/Banded_iron_formation

    Banded iron formation from the Barberton Greenstone Belt, South Africa. A typical banded iron formation consists of repeated, thin layers (a few millimeters to a few centimeters in thickness) of silver to black iron oxides, either magnetite (Fe 3 O 4) or hematite (Fe 2 O 3), alternating with bands of iron-poor chert, often red in color, of similar thickness.

  7. Iron-rich sedimentary rocks - Wikipedia

    en.wikipedia.org/wiki/Iron-rich_sedimentary_rocks

    Iron formations can be divided into subdivisions known as: banded iron formations (BIFs) and granular iron formations (GIFs). [ 3 ] The above classification scheme is the most commonly used and accepted, though sometimes an older system is used which divides iron-rich sedimentary rocks into three categories: bog iron deposits , ironstones , and ...

  8. Gunflint chert - Wikipedia

    en.wikipedia.org/wiki/Gunflint_Chert

    The Gunflint Iron Formation is a banded iron formation, composed predominantly of dense chert and slate layers interbedded with ankerite carbonate layers. The chert layers can be subdivided into black layers (containing organic material and pyrite), red layers (containing hematite), and green layers (containing siderite). [5]

  9. Iron cycle - Wikipedia

    en.wikipedia.org/wiki/Iron_cycle

    Iron reaches the atmosphere through volcanism, [8] aeolian activity, [9] and some via combustion by humans. In the Anthropocene, iron is removed from mines in the crust and a portion re-deposited in waste repositories. [4] [6] The iron cycle (Fe) is the biogeochemical cycle of iron through the atmosphere, hydrosphere, biosphere and lithosphere.