Economic Geology
Mineral
deposit types
Based on ProMine’s European mineral database and corresponding ore deposit types
classification, feasible gold
mineralisations in Europe are found, either as major or associated commodity,
in Epithermal, Orogenic, Igneous Intermediate/Porphyry Copper, Iron Oxide Copper Gold (IOCG), Volcanogenic Massive Sulphide (VMS) and
Carbonate Replacement Polymetallic ore deposits. http://www.europe-geology.eu/mineral-resources/mineral-resources-map/precious-metal-map/
Mineral exploration potential belts
in Europe
Minor epithermal (Au, Ag, Sb, Hg, Te, Cu, In) and volcanic group potential can be found in the Fennoscandian Shield and western Europe Hercynian domain. On the other hand, the potential is much higher along the Tethyan suture, in south-eastern Europe, especially between Slovakia and Greece. The Carpathian-Balkan region, with its various epithermal and porphyry districts, is well known and form a semi-continuous belt which includes Kremnica in Slovakia, Telkibanya in Hungary, Baia Mare and Apuseni Mountains in Romania, Bor in Serbia, Assarel in Bulgaria and the eastern Rhodopes (Madan group in Bulgaria and Perama in Greece). Farther south, in the Balkan domain, epithermal type mineral deposits are more scattered. Of particular note is the Trepča district, in Kosovo, that combines carbonate-related and epithermal types.
The distribution of Orogenic Gold , Au, (Ag, As, W, Cu, Sb, Bi), deposits is relatively straightforward as it is characterized by a single main commodity and a well-constrained type of mineralization. Major known gold-bearing districts belong to two groups: Paleoproterozoic orogenic deposits in the Fennoscandian Shield; and Hercynian gold-bearing districts in the northern Iberian Peninsula, the French Massif Central and the Bohemian Massif. Additional more scattered deposits can be found in other Hercynian domains (e.g. Salsigne in southern France, the Caledonian domain (Great Britain and Norway) and the Balkan-Carpathian domain.
Igneous
intermediate mineralization (i.e. porphyry type, Cu, Mo, Au,
(Re), is typically related to the evolution of the
western Tethyan suture in the late Cretaceous and Cenozoic, especially in
Eastern Europe where there is high potential for additional deposits. In
Eastern Europe, the Upper Cretaceous in
the Tethyan margin, contains large porphyry-type districts, of which
most were subsequently reactivated and are associated with epithermal-type
ores. The most important are Kremnica in Slovakia, Telkibanya in Hungary, the
Apuseni Mountains in Romania, Bor in Serbia, Assarel in Bulgaria and Bucim in
North Macedonia. Other domains also host porphyry-type mineralization, of older
age, although their classification as belonging to this deposit type is still
debated. In the Fennoscandian Shield, several Cu-(Au)- or Cu–Mo-bearing Palaeoproterozoic
deposits are described as porphyry style. The most important are Aitik (Cu–Au)
and Tallberg (Cu–Au, Skellefte district), both in Sweden, and Kopsa (Au–Cu)
related to a tonalite stock in the Hitura belt (in Finland). In relation to the
Caledonian volcanism, there are a few smaller porphyry-type deposits of Lower
Palaeozoic age in Great Britain, such as Coedy Brenin (Wales) and Black
Stockarton Moor (Scotland). Hercynian magmatism in the Upper Palaeozoic is
associated, especially in France, with Cu–Mo–W porphyry deposits, although
their geodynamic context is poorly described (e.g. Beauvain, Mo; Sibert, Cu;
Auxelles-le-Haut, W). There is also porphyry Mo mineral of various ages in
Europe. The most important of these is probably Nortli in Norway, a group of
deposits related to Permian intrusions in the Oslo rift.
This IOCG type, Fe, Cu, Au, (P, REE, U, Co), of mineralization can be found essentially in two Paleoproterozoic districts in the Fennoscandian Shield. The most important is Kiruna (northern Sweden), which is a type locality for IOCG, and the other one is Bergslagen (central Sweden). These districts contain large world-class iron deposits, with a typical magnetite-apatite paragenesis and sodium alteration. These districts also contain copper sulphide deposits that are interpreted as VMS (Viscaria) or porphyry (Aitik). More limited IOCG style deposits are also known in other parts of Europe. Some Fe (Fe–Cu) IOCG style deposits are identified in the Ossa Morena Zone in southwestern Iberia. They are mesozonal albitite-related magnetite deposits and are interpreted as being related to either residual melts of rift-related juvenile magmas (Cambrian) or anatexis of earlier mineralization during high T/low P metamorphism along major shear zones of Variscan age.
The distribution of deposits of this type clearly highlights the major known VMS type ,Cu, Zn, Pb, (Ag, Au, Te, Sn, In), provinces: The Palaeoproterozoic districts of Skellefte and Bergslagen, in Sweden, and Vihanti- Pyhäsalmi and Outokumpu, in Finland; The Upper Palaeozoic (Devonian, Carboniferous) district of the southern Iberian province (e.g. Rio Tinto in Spain, Neves Corvo in Portugal) in Spain and Portugal; The Upper Cretaceous VMS district in Cyprus (Skouriotissa, Mavrovouni, Limni), related to the Troodos ophiolite complex. In addition to these three major mineralized provinces, there are several other smaller deposits. In Scandinavia, copper-rich stratiform sulphides formed in the Palaeozoic along the Caledonian domain. They could be VMS deposits of various types (e.g. Röros VMS in back arc setting, Tverrfjellet and Joma VMS of Besshi type, Sulitjelma VMS of Cyprus type). These mineral deposits seem to extend southward into the Dalradian Caledonian domain of Scotland (e.g. Ben Collum, Auchtertyre). Other VMS mineralization, of Devono-Carboniferous age, can be found in the European Hercynian domain. In France(Châteaulin basin, Saint-Georges-sur-Loire and Chessy), several volcanic related deposits have ages similar to those in the southern Iberian Province (Upper Devonian and Tournaisian). Their tonnages, however, are much smaller. In other parts of the Hercynian domain, massive sulphide deposits are preferentially of SEDEX type (e.g. Rammelsberg and Meggen in Germany, Rhinish-Hercynian domain. In the Navandistrict (Ireland), they are hosted in a Carboniferous foreland sedimentary basin. In addition, there are also numerous mineral deposits or groups of mineral deposits (with various commodities) where the classification is still debated. This is the case, in particular, for iron deposits in the Alps and the Balkan-Carpathian domain that were classified as SEDEX. They could in fact be replacement deposits (e.g. Ljubija and Omarska in Bosnia and Herzegovina, Erzberg in Austria). Mercury and copper deposits (e.g. Idrija in Slovenia, Munella in Albania), classified as SEDEX could also be epithermal.
Igneous carbonate replacement (Fe, W, Pb, Zn, Cu, Au) or skarn deposits occur where carbonate rocks are cut by younger intrusions. In Europe, they are distributed in three major domains: (i) the Precambrian Fennoscandian Shield, (ii) the Hercynian domain in southern Europe, and (iii) the Cenozoic Carpathian-Balkan domain. The Fennoscandian Shield contains iron deposits in greenstones of the Lappland Palaeoproterozoic domain (e.g. Puoltsa, Sautusvaara and Stora Sahavaara in Sweden, Kolari district in Finland). These deposits are related to ‘magnetite-enriched formations and Ca–Mg calc-silicates’, spatially associated with BIFs or Kiruna type IOCG. Recent studies in the Kolari area in Finland (i.e. Laurinoja and Kuervitikko Rautuvaara) show that metasomatized replacements are preferentially IOCG type facies rather than typical ‘intrusion-related skarn deposits. In the Bergslagen district in Central Sweden skarn mineralization is hosted by Paleoproterozoic marbles intruded by post-tectonic granites (1.8 Ga). Examples of such deposits include the Yxsjöberg “scheelite-skarn deposit”, skarn iron lenses and skarn iron-sulphides lenses of Stollberg (Fe–Pb– Zn–Mn (Ag)), and sulphide skarn of Garpenberg (Zn). The Arendal (Klodeborg) iron deposit in Norway comprises magnetite skarn in Mesoproterozoic sequences (1.2–1.5 Ga) cut by younger intrusions (0.9–1 Ga), and the Knaben deposit (same age) is located in gneisses, paragneisses and amphibolites. In the southern part of the Hercynian domain, well-developed Palaeozoic (Cambrian and Devonian, essentially) carbonate layers and Hercynian (Upper Carboniferous, 310 Ma) magmatism allowed the development of tungsten- (and/or magnetite-) bearing skarns in the Pyrenees, the southern Massif Central, in Sardinia and in the Alps. The northern parts of the Hercynian arc display only minor occurrences, essentially because of the lack of Palaeozoic carbonate units. In the Balkan-Carpathian domain, numerous carbonates, essentially of Mesozoic age, and Upper Cretaceous-Cenozoic magmatic episodes allowed development of numerous replacement deposits in the vicinity of epithermal and porphyry domains. Important examples include Kremsica, Baia Mare, Bor, Madan, Trepča and Olympias in northern Greece. Minor deposits of this group can also be found in the western Mediterranean, related to Tertiary and Quaternary magmatic episodes in Spain, Sardinia (e.g. Calabona skarn associated with a dacitic porphyry copper) and close to Elba.
Resources
and reserves
