Hercynian granite

Simon, K. Hoefs, J. (1987). Effects of meteoric water interaction on Hercynian granites from the Sudschwarzwald, SW Germany. Chemical Geology, 61, 253-61. 

The uranium and thorium contents of the different Hercynian granites and of the pre-existing Palaeozoic rocks are given in Table 2. ... 

It is therefore proposed that, on the basis of the studies of British Caledonian and Hercynian granites, in a search for vein-type hydrothermal mineralization in high heat production... 

Occurrences in recant sediments overlying Hercynian granites... 

Di Vincenzo G., Andriessen P. A. M., and Ghezzo C. (1996) Evidence of two different components in a Hercynian peraluminous cordierite-bearing granite the San Basilio intrusion (central Sardinia, Italy). J. Petrol, yi, 1175-1206. 

The European HDR project site at Soultz-sous-Forets is located on a local horst structure in the Rhine Graben, where Hercynian age granites are covered by a 1.4 km thick sedimentary section (Baria et al., 1999). Well GPK-1 was drilled to 3,590 m depth (open hole below 2,850 m depth), and since 1987 it has been used for a number of... 

Uranium deposits in this unit are of numerous geological types, but three are typical of the Hercynian orogen (1) intra-granitic deposits related to leucogranites, (2) deposits bound to the contact-metamorphic haloes of granite intrusives in Lower Palaeozoic shales (the so-called Iberian type ) and (3) deposits bound to Permian cover rocks or Permian acid volcanics. Other types are veins in less differentiated granites, veins in metamorphic environments, sandstone-type deposits in Mesozoic or Caenozoic cover rocks in basin structures of the Hercynian space included in or adjacent to the Moldanubian zone (or its Iberian equivalent). 

In Europe the privileged zone of occurrence of this type of deposits seems to be the outer zone immediately bordering the inner zone of the Hercynian orogen, characterized by maximum metamorphism and granitization. It is, in particular, the case in the Iberian Peninsula, where these deposits are scattered within sub-zone b) of the Central Iberian zone of Fig. 1. In Bohemia, however, the Pribram and Jachymov districts belong to the Moldanubian zone, though being attributable to the same type of deposit. 

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