Abstract: This paper explains the terminology and a classification scheme which are used in an accompanying paper about the genesis of iron formations. An iron formation is considered to be a stratigraphic unit which consists mostly of iron-rich chemical sedimentary rock, specifically rock with more than 15% Fe.∗ The rock is called ironstone. Iron formations may be classified into six groups on the basis of the sedimentary environment in which they accumulated. Some previous authors have used the terms, ironstone and iron formation, in more restricted ways. For example, "ironstone" has been used to name one of the six environmental types of iron formations and "iron formation" has been used exclusively for chert-rich iron formations. These restrictions are avoided herein because they are not consistent with the simplicity of the names. By analogy with limestone, ironstone is simply an iron-rich chemical sedimentary rock. The word, formation, clearly refers to a stratigraphic unit and so "iron formation" is applied to any stratigraphic unit which is composed predominantly of ironstone. Alternative usages of the terms, ironstone and iron formation, have been sufficiently varied that none of the usages can be defended on the grounds of overwhelming support, independent of semantic arguments.
Publication Year: 1989
Publication Date: 1989-12-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 31
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