Environmental Engineering Reference
In-Depth Information
Figure 12.9
Some standard schemes for classifying
sedimentary rocks (a) by particle size and (b) by mineral
content; the numbers are percentages. (c) Below these
ternary diagrams the British Standards Institute and US
Department of Agriculture define particle size and their
millimetre and micron size ranges.
Figure 12.10
Origins and classification of the principal
sedimentary rocks.
Source: After Newton and Laporte (1989).
increase with time in transit, reflecting clast-to-clast collision. Comparisons between
compact and platy grain shapes indicate lithological distinctions between massive and
schistose/laminated parent rocks. Attrition also reduces particle size, whereas sorting
