Measurements in three dimensions: strike and dip, formation thickness and depth
We are beginning to see why geological maps are such a powerful and convenient means of conveying information about the three-dimensional configuration of rocks. Nevertheless, it is often necessary to specify the arrangement in words or numbers. Geologists do this by using the concept of strike and dip. The general idea was introduced in section 2.3.1; the first part of this chapter explains it in detail. The second part of the chapter expands on methods of subsurface projection and some useful measurements that can be made from maps. These techniques are of use in applied geology where, for many purposes, the work will have to be done as accurately as possible, especially if sums of money are at risk. Some of the corrections that may have to be borne in mind for this kind of mapwork are introduced.
KeywordsHorizontal Distance Coal Measure Strike Direction Vertical Thickness Formation Depth
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