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PROSPECTING FOR METALLIC ORES AND PRECIOUS METALS IN THE CAMBRIAN REGION OF THE WESTERN MEDITERRANEAN (CEVENNES, FRANCE - SARDINIA, ITALY)

Cel

The aim of this research project is to define the requirements for high concentrations and to draw up prospecting guides for the hidden deposits in the carbonate areas of the region of the western Mediterranean which is high in mineral deposits (Cevennes, France and Iglesiente, Italy).
A correlation attempt has been reported between the Lower Paleozoic Iglesiente (southwest Sardinia) and Southern Cevennes Montagne Noire Variscan domains, with particular regard to the Cambrian hosted economic lead zinc concentrations and the spatially associated precious metal (gold) occurrences. Geological, lithogeochemical and lead isotope investigations allowed the following results. The major lead-zinc deposits of Iglesiente and Southern Montagne Noire have Mississippi Valley type origin, involving remobilization of preexisting Cambrian syngenetic ores and metal anomalies during the Ordovician distensive 'Sardic phase'. Lead isotope evidence suggests mixed crustal sources for Iglesiente lead. The Southern Cevennes stratiform 'Minerai Zero' of the Malines district is not syngenetic with Cambrian host rocks. For this ore type a syn to late tectonic Variscan formation model is proposed, similar to the model indicated for the genesis of the Salsigne gold deposit in the Montagne Noire. A reevaluation is therefore suggested of the Vigan gold occurrences, regionally associated with the 'Minerai Zero' economic lead zinc bodies. The newly discovered Tertiary epithermal gold province of Sardinia is genetically quite distinct from the Paleozoic lead zinc province of Iglesiente.
The work programme will be divided into the following parts in each of the 2 regions.

The first part is geological studies on the ground and in mines. This initial data gathering part will consist of ground operations in the Horst of St Bresson in the Southern Cevennes and the Iglesiente in south western Sardinia, and mine observations (mines of Campo Pisano, Masura, Monteponi, San Giovanni-Seddas Modizis in Sardinia). The purpose of this phase is to establish the sediment, mineral and structural parameters of the mineral bearing sectors and the sectors considered to be barren. The results obtained during the initial part will provide a basis for sampling for the geochemical, mineralogical and geochronological analyses in the second and third parts.

The second part is geochemical and mineralogical analyses. Analyses will be carried out to establish the specific geochemical and isotopic signatures of the various ore bearing concentrations and to define the signature gradients of the deposits. The geochemical (main and trace elements), isotopic (carbon, oxygen and lead) and mineralogical signatures of the deposits and the environment will be established. The work will focus in particular on the high level concentrations.

The third part is geochronological analyses. These analyses will supplement the data which already exists on the Hercynian and ante Hercynian formations of the Cevennes bed and southern Sardinia.

The fourth part is structural and microstructural studies. The aim of these studies is to determine the age of the Cambrian enveloping mineral at Malines (Cevennes, France). The studies will consist of: fine analysis of the intercrystalline textures of the mineral and the enveloping strata and comparison with the deformed Cambrian minerals of southern Sardinia; a joint structural study of the bed and its sedimentary cover (Trias, Lias); and exploration of the tectonic phase associated with the Liassic remobilization which is poorly defined in the south of the Massif Central (France). The methods used will be conventional microtectonic analysis and fine analysis of the textures, including the calcite macle method, to determine the relative chronology of the deformation phases.

The last part is data sheets for the deposits and modelling. The data on the deposits gathered during the preceding stages will be summarized in the form of multiparameter data sheets, which will be used: to set out the main concentration factors for the base and precious metals; to draw up corresponding prospecting guides; and to model the deposits.

Temat(-y)

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Zaproszenie do składania wniosków

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System finansowania

CSC - Cost-sharing contracts

Koordynator

Società Italiana Miniere SpA
Wkład UE
Brak danych
Adres
Monte Agruxau
09016 Iglesias Cagliari
Włochy

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Koszt całkowity
Brak danych

Uczestnicy (7)