“Structural Control” remains a crucial point that is frequently absent in scientific and/or economic analyses of ore deposits, whatever their type and class, although a selection of references illustrates its importance [1–5]. The case of lode deposits is particularly adapted, but other types, like breccia pipes, stockwork, massive sulphides, skarn, etc., also concern Structural Control. Works on the Structural Control of ore deposits are not abundant in the recent literature, and, as frequently suggested, structural geology often is not sufficiently developed in the exploration programs of many mining camp’s strategies.

A geological map is a medium of communication that uses graphic symbols to represent spatial relationships among geographical and geological feautures. Lines, points, symbols, and texture markings are used to separate various classes of information. But the interpretation of geological maps goes beyond identifying the individual items displayed on the map. A connection must be made between what is perceived on the map and other knowledge. The interpretation of geological maps is basically an attempt to visualize and understand the complex shapes of rock units in the subsurface. A thorough understanding of the variety of geological structures is particularly important, because it helps to determine the nature of subsurface structures from geological maps. Structural geology, therefore, is a major cornerstone of the art of geological map interpretation. <...>

The fi eld trip described in this guide starts in the “Norwegian Alps,” the high mountain massif called Jotunheimen, and runs out along Sognefjorden, the world’s longest fjord, to the islands along the west coast of Norway. Geologically, the Sognefjord transect provides a complete cross section through the Caledonian orogenic belt, of Paleozoic age, which in Norway stretches along the west coast from Stavanger to North Cape, a distance of ~2000 km.

Structural geology deals with the deformation of rocks. After their formation, sedimentary and igneous rocks may remain undisturbed or are deformed to different degrees. A volume of rock may change shape, rotate bodily, fracture or be displaced from one place to another. Such changes may be visible to us, for example, by the tilting of horizontal strata, by development of folds in originally planar beds, by distortion of pebbles, fossils and mineral grains in rocks and by the fragmented character of an originally continuous bed. If these features are in a large scale, their three-dimensional forms are not visible to us; they can be studied only on the eroded surface of the earth. One of the primary objectives of structural geology is to determine three-dimensional forms of these structures mainly from observations on the surface. The first step of structural analysis of an area is to study the geometry of the structures, i.e. to study their morphology and orientation (or attitude), both by direct observation of small structures in the outcrop and by reconstruction of large structures <...>