Title: Evaporites, cherts, iron-rich sedimentary rocks, and phosphorites
Abstract: This chapter deals with the chemical/biochemical rocks other than carbonates. Thus, it discusses evaporites, the siliceous sedimentary rocks (cherts), iron-rich sedimentary rocks (iron-formations and ironstones), and phosphorites. Volumetrically, these rocks are far less abundant than siliciclastic sedimentary rocks and carbonate rocks. If we add the percentages of shale, sandstone, and carbonate rocks calculated or measured by various authors such as Ronov et al. (1980), the unaccounted volume of total sedimentary rocks that can be attributed to these chemical/biochemical rocks appears to be no more than about 2 percent. The small volume of these rocks is not, however, a measure of their importance or the interest that we have in them. All of the sedimentary rocks discussed in this chapter have considerable economic significance. Evaporite deposits such as gypsum, halite (rock salt), and trona are mined for a variety of industrial and agricultural purposes, iron-rich sedimentary rocks are the source of most of our iron ores, phosphorites are extremely important sources of fertilizers and other chemicals, and the siliceous sedimentary rocks have some economic value, e.g. in the semiconductor industry.
Publication Year: 2009
Publication Date: 2009-02-19
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 2
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