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Silicate minerals
About: Silicate minerals is a research topic. Over the lifetime, 1794 publications have been published within this topic receiving 67064 citations.
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TL;DR: In this article, the authors use thermodynamic calculations to show that Fe and Si-rich fluids can be generated by hydrothermal leaching of low-Al oceanic crustal rocks such as komatiites.
Abstract: Banded iron formations are plentiful in the rocks representing early Earth, but the mechanisms by which they formed remain controversial. Geochemical modelling indicates that the hydrothermal leaching of low-aluminium ocean crust and subsequent chemical reactions in iron- and silica-rich hydrothermal fluids could have triggered the alternating deposition of iron and silica-dominated sediments. The chemical signatures and mineralogy of banded iron formations have the potential to provide information about the ocean environment on early Earth1,2,3,4,5,6,7. Their formation requires iron- and silicon-rich fluids, but the mechanisms by which the alternating layers of Si- and Fe-rich rock formed remain controversial8,9,10,11. Here we use thermodynamic calculations to show that Fe- and Si-rich fluids can be generated by hydrothermal leaching of low-Al oceanic crustal rocks such as komatiites. We find that positive feedbacks occur among the chemical reactions when hydrothermal fluids mix with ambient sea water. These feedbacks lead to alternating precipitation of Fe and Si minerals, owing to the formation of complexes between Fe(II) and silicic acid. We suggest that the small-scale (<1 cm) banding was produced by internal dynamics of the geochemical system, rather than any external forcing. As the Archaean eon progressed, the oceanic crust produced was rich in Al12. When Al-rich crust undergoes hydrothermal alteration, Fe is locked in Al–Fe silicate minerals. This results in iron-depleted hydrothermal fluids, and thus prevents the deposition of Fe-rich minerals. We therefore conclude that the widespread cessation of banded iron formation deposition 1.7 billion years ago reflects the changing composition of the oceanic crust.
50 citations
TL;DR: It is demonstrated that plants can obtain K for growth from milled syenite, in which feldspar is the dominant K-bearing mineral, and previous observations that micas can be an effective source of K are confirmed.
50 citations
TL;DR: A comprehensive approach is expected to firmly establish the connection between selective cleavage of mineral crystals for desired surfaces and designing novel reagents selectively adsorbed on the mineral surfaces to develop effective relational models comprising their crystal structure, surface chemistry properties, and targeted reagent adsorption.
50 citations
TL;DR: In this paper, the dominant mechanism responsible for adsorption of nonionic organic compounds on different cation-modified clay minerals (i.e. smectite, kaolinite, and vermiculite) was explored.
50 citations
TL;DR: From one-fourth to one-half of the nitrogen in some granite rocks, and up to two-thirds of that in some paleozoic shales, occurred as ammonium ions held within the lattice structure of silicate minerals.
Abstract: From one-fourth to one-half of the nitrogen in some granite rocks, and up to two-thirds of that in some paleozoic shales, occurred as ammonium ions held within the lattice structure of silicate minerals. The results provide greater insight into the origin of the earth's atmosphere.
50 citations