Raiswell R, Canfield D E, Berner R A
Department of Earth Sciences, Leeds University, UK.
Chem Geol. 1994;111:101-10. doi: 10.1016/0009-2541(94)90084-1.
Measurements of degree of pyritisation require an estimate of sediment iron which is capable of reaction with dissolved sulphide to form pyrite, either directly or indirectly via iron monosulphide precursors. Three dissolution techniques (buffered dithionite, cold 1 M HCl, boiling 12 M HCl) were examined for their capacity to extract iron from a variety of iron minerals, and iron-bearing sediments, as a function of different extraction times and different grain sizes. All the iron oxides studied are quantitatively extracted by dithionite and boiling HCl (but not by cold HCl). Both HCl techniques extract more iron from silicates than does dithionite but probably about the same amounts as are potentially capable of sulphidation. Modern sediment studies indicate that most sedimentary pyrite is formed rapidly from iron oxides, with smaller amounts formed more slowly from iron silicates (if sufficient geologic time is available). It is therefore recommended that the degree of pyritisation be defined with respect to the dithionite-extractable (mainly iron oxide) pool and/or the boiling HCl-extractable pool (which includes some silicate iron) for the recognition of iron-limited pyritisation.
黄铁矿化程度的测量需要估算沉积物中铁的含量，这些铁能够与溶解的硫化物直接或通过单硫化铁前体间接反应形成黄铁矿。研究了三种溶解技术（缓冲连二亚硫酸盐、冷1M盐酸、沸腾的12M盐酸）从各种铁矿物和含铁沉积物中提取铁的能力，该能力是不同提取时间和不同粒度的函数。所研究的所有铁氧化物都能被连二亚硫酸盐和沸腾的盐酸定量提取（但不能被冷盐酸提取）。两种盐酸技术从硅酸盐中提取的铁比连二亚硫酸盐多，但可能与潜在可硫化的铁量大致相同。现代沉积物研究表明，大多数沉积黄铁矿是由铁氧化物快速形成的，少量是由铁硅酸盐更缓慢形成的（如果有足够的地质时间）。因此，建议针对连二亚硫酸盐可提取（主要是铁氧化物）库和/或沸腾盐酸沸腾盐酸可提取库（包括一些硅酸盐铁）来定义黄铁矿化程度，以识别铁限制的黄铁矿化。
