The Ivrea crustal cross-section (northern Italy and southern Switzerland) (Andre Zingg)
The exposed crustal cross section of southern Calabria, Italy: structure and evolution of a segment of Hercynian crust (Volker Schenk)

An exposed cross-section of continental crust, Doubtful Sound Fiordland, New Zealand; geophysical & geological setting (G.J.H. Oliver)
Uplift and exhumation of middle and lower crustal rocks in an extensional tectonic setting, Fiordland, New Zealand (G.M. Gibson)

Copper is most commonly present in the earth’s crust as coppereironesulfide and copper sulfide minerals, such as chalcopyrite (CuFeS2) and chalcocite (Cu2S). The concentration of these minerals in an ore body is low. Typical copper ores contain from 0.5% Cu (open pit mines, Fig. 1.1) to 1 or 2% Cu (underground mines). Pure copper metal is mostly produced from these ores by concentration, smelting, and refining (Fig. 1.2). Copper also occurs to a lesser extent in oxidized minerals (carbonates, oxides, hydroxy-silicates, sulfates). Copper metal is usually produced from these minerals by leaching, solvent extraction, and electrowinning (Fig. 1.3). These processes are also used to treat chalcocite (Cu2S).
A third major source of copper is scrap copper and copper alloys. Production of copper from recycled used objects is 10 or 15% of mine production. In addition, there is considerable re-melting/re-refining of scrap generated during fabrication and manufacture. Total copper production in 2010 (mined and from end-of-use scrap) was ~20 million tonnes. <...>

The term rare earths denotes the group of 17 chemically similar metallic elements that includes scandium, yttrium, and the lanthanides (Spedding 1978; Connelly et al. 2005). The lanthanides are the series of elements with atomic numbers 57 to 71, all of which, except promethium, occur in nature. The rare-earth elements, being chemically similar to one another, invariably occur together in minerals and behave as a single chemical entity. Thus, the discovery of the rare earths themselves occurred over a period of nearly 160 years, from 1787 to 1941 (Szabadvary 1988; Weeks 1956).

Features of recent sediments and ancient sedimentary rocks can be combined and condensed into idealizations or models that characterize particular sedimentary environments. This combination of features from modern and ancient situations has been emphasized from the earliest days; in 1893 Johannes Walther (quoted by Middleton, 1973, p. 981) "explained that the most satisfying genetic explanations of ancient phenomena were by analogy with modern geological processes".