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Folds Descriptors |
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Geologist have invented various methods to characterise the geometry of folds. One of these involves the use of the Stereonet. It is based on the fact that the plunge and plunge direction of the fold axis, as well as the fold geometry, can be deduced from the distribution of poles (π) to the folded surface. On a stereogram, the B axis corresponds to the pole of the great circle which best fits the distribution of poles to the folded surface. This great circle is called the π circle. |
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Alternatively the B axis can be inferred from the intersection, on a stereonet, of surfaces (β) tangent to the folded surface. The sketches below illustrate the relationship between the distribution of π poles and the fold's geometry. |
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