Page 80 - Atlas of Sedimentary Rocks Under The Microscope
P. 80
Other sedimentary rocks
I n troduction
In this section we include phoLOgraphs of thin sections of ironstones,
evaporites, cherts, phosphorites and carbonaceous rocks. Even taken
together, these rock types form a very small proportion of the total
sedimentary record. However these groups of rocks have always
attracted petrographic Study out of proportion to their abundance,
partly because they include rocks of great economic importance and
partly because they show unusual fe atures which have attracted
considerable interest.
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