The new European Research Programme on Ore Deposits GEODE

From the Steering Committee Chairman of the GEODE Programme
Derek J. Blundell

Department of Geology , Royal Holloway, University of London Egham, Surrey, TW20 0EX, UK

On 1 April 1998, the European Science Foundation (ESF) launched its new scientific programme on Geodynamics and Ore Deposit Evolution, GEODE, for a five year term. GEODE aims to build a quantitative understanding of the geological processes on all scales that lead to the formation of world class ore deposits, particularly in their timing and location. The research programme is built around projects centred on five metallogenic provinces, all of which contain world class ore deposits. These are the Alpine-Carpathian Chain, the Iberian Pyrite Belt (plus Massif Central), basin hosted deposits (Irish base metal and Polish Kupferschiefer), the Urals and the Fennoscandian Shield Precambrian (including Greenland and Ukraine) mineral provinces. They may be supported by projects in South America and the SW Pacific region specifically aimed at providing insights that can be applied to give a better understanding of ore deposit types in Europe. The programme divides into studies of metallogenic provinces in orogenic systems active at the present day and studies of metallogenic provinces from the geological past. Only with modern systems is it reasonable to relate the mineralising processes to the present day large-scale structure and properties of the lithosphere which are determined from the geophysical information, although the lithospheric structure of the Urals orogen does appear to have been preserved since the time it was active. GEODE is particularly timely because it can take advantage of the major new findings about geodynamic processes in the Alps and Carpathian Chain, the Urals, SW Iberia and the Fennoscandian Shield coming from the EUROPROBE programme. GEODE is building closer collaboration amongst scientists across a wide range of disciplines from research institutions, geological surveys and the mining industry in order to focus their attention upon the nature and genesis of world class ore deposits. The five projects involve:-

The Alpine-Carpathian Chain

Working Group Convenor: Prof. Franz Neubauer (Franz.Neubauer@sbg.ac.at),
University of Salzburg, Department of Geology, Resindenzplatz 1, 5020 Salzburg, Austria.

The Alpine-Carpathian Chain provides a number of specific tectonic environments, chiefly convergence, collapse and rifting, reflecting the underlying known geodynamic behaviour of the subduction zone. The prime mineralising system is the Carpatho-Balkans region of convergence and collapse, characterised by porphyry and epithermal styles of mineralisation and where it is known that, during the late stages of continental collision and orogenic collapse, asthenospheric melts generated by slab break-off may have played a prominent role in generating an additional heat source and essential chemical components. Also of importance in the Alpine-Carpathian Chain is the effect of spreading rates within the Tethyian Spreading Centre and their temporal and spatial variations with respect to the ophiolite hosted mineralisation, for example Albania (chromite) and Cyprus (sulphides/chromite). This province provides a natural laboratory to study the world's major style of copper mineralisation (porphyry), and the second or third most important style of gold mineralisation (epithermal).
Through the work of Europrobe, this chain has a comprehensive database related to deep structures and thermal anomalies through extensive tomographic and seismic studies. In addition, through tectonophysical modelling, the evolution of these structures and anomalies is particularly well characterised. Linking on to Europrobe, the GEODE project will take full advantage of the huge amount of new knowledge that is accruing about the thermo-tectonic and structural evolution of the region and use this to concentrate on the mineralisation processes of specific deposits.

The Iberian Pyrite Belt

 Working Group Convenor: Prof. Fernando Barriga (Fernando.Barriga@fc.ul.pt),
Dep.Geologia, Fac. Ciencias, Universidade de Lisboa, Edificio C2, Piso 5, Campo Grande, 1700 Lisboa, Portugal.

This province contains some of the world's largest concentrations of volcanic-hosted base metal deposits, such as Neves Corvo in Portugal, Aznalcollar-Los Frailes and the newly discovered Las Cruces deposit in Spain. It is a current focus for international exploration and is already the subject of a Europrobe project. This is investigating transpressional orogeny in this part of the Variscide orogen specifically in order to place the massive sulphide ore deposits within their tectonic setting. Through collaboration with the Europrobe project team, GEODE can bring greater impact to the research by using its coordinated approach to analysing mineralisation processes. This research will extend to studies of the mineralisation of the Massif Central and NW Iberia, especially in the fields of geochronology, fluid chemistry and the modelling of the palaeo-hydrology of subaqueous hydrothermal systems that form giant VHMS deposits.

Basin-hosted deposits

Working Group Convenor: Prof. Willy Viaene (willy.viaene@geo.kuleuven.ac.be),
KU Leuven, Afdelung Fysico-chemische Geologie, Celestijnenlaan 200C, 3001 Leuven, Belgium.

World class sediment-hosted base metal deposits include the classic carbonate hosted lead-zinc Navan ore deposit in Ireland and the major Kupferschiefer copper deposits of Poland. The Irish Pb-Zn-Ag and the Kupferschiefer Cu deposits formed in basins that developed in the foreland of or postdated the Variscan Orogeny. The absence of later deformation makes them ideally suited to metallogenetic research, in contrast to their giant equivalents in the Precambrian of Canada, central Africa and Australia, which are mostly disturbed by later deformation. The Kupferschiefer is the best example of the world's second most significant style of copper mineralisation and can provide important insights which could be applied elsewhere in the world (e.g. Zaire and Zambian copperbelt; Udokan in Eastern Russia, etc.). It is also of value to search for the source of gold and platinum group elements in the Kupferschiefer. Irish Carboniferous lead-zinc deposits represent a class of mineralisation for which a range of models of either Sedex or replacement origin exist. Their excellent mineralogy and grade make them a world-class target and thus there is a need for a much more clearly defined model. Success in exploration for new deposits of both types depends on sophisticated exploration concepts because they are generally buried under shallow cover.

The Urals Mineral Province

Working Group Convenor: Prof. Krister Sundblad (Krister.Sundblad@geo.ntnu.no),
Dept. of Geology and Mineral Resources Engineering, NTNU, N-7034 Trondheim, Norway.

This region remains a frontier area for mineral exploration, containing major volcanic-hosted VHMS deposits such as Degtiarskoe, Uchalinskoe, Sibay and Gai, the Magnitogorskoe skarn-hosted magnetite deposits and the ophiolite-hosted chrome deposit at Kempirsai. These deposits are at least an order of magnitude larger than average deposits in the same geological settings elsewhere in the world. Deeper mantle processes may hold the clue to the striking productivity of this collision belt. A well advanced Europrobe project has produced superb structural and tectonic information about the orogen, which has retained its crustal and lithospheric roots. Recent studies from Europrobe show that the southern Urals is currently marked by an anomalously low geothermal gradient which has resulted in excellent preservation of original deposit features, where even hydrothermal vent fauna associated with VHMS deposits are recorded. This indicates that the region is an ideal area to study ore-forming processes because the ore deposits have suffered less overprint by post-formation events. GEODE will build on Europrobe by focusing on the mineralisation.

The Fennoscandian Shield Precambrian Province

Working Group Convenor: Dr. Pår Weihed (weihed@algonet.se),
Geological Survey of Sweden, Box 670, 751 28 Uppsala, Sweden.

In common with many other early Precambrian provinces, the Fennoscandian Shield is metal rich, and has for a long time been a major source of metals in Europe. Exploration is active and ongoing, and the recent discoveries of a major diamond deposit on the White Sea coast near Archangel and of gold deposits in the Proterozoic and Archean greenstone belts of Eastern Finland have added further interest to the province.

GRANTS FOR VISITS

To give this new programme a strong start, the GEODE Scientific Steering Committee wants to support short visits by active researchers and doctoral students to a research institution (e.g. University, Geological Survey) in another European country for laboratory and/or field work in order to build new research partnerships and facilitate new funding proposals for collaborative, multidisciplinary research. See the GEODE website http://www.gl.rhbnc.ac.uk/geode/ for details of the Grants for Visits scheme and how to make an application. The deadline for applications is 31 January 1999 for visits to begin from 15 March 1999, although the Steering Committee may set a subsequent deadline for a later set of grants if they feel it is warranted.
The shield has been well studied geologically and geophysically, but many of the major deposits remain enigmatic, at least in part because complex deformation and metamorphism of host sequences have hindered interpretation of tectonic settings. Significant deposits of interest are the iron ore deposits of Kiruna, and the iron-oxide associated base metal deposits at Aitik and Bergslagen, which are now gaining recognition as being part of a suite of deposits that includes world class deposits of copper, gold and uranium in Australia and South America, and are therefore of current international interest. Significant base metal Cu ± Zn ± Ni ± Co deposits include those at Pechenga and Outokumpu, and are variably hosted in mafic-ultramafic suites and associated sedimentary sequences. It is likely that the application of new techniques in geochronology and geochemistry will further our understanding of the ore deposits of this province. The project will include the Precambrian of Greenland and the Ukraine along with Fennoscandia.
GEODE is managed through ESF by a Scientific Steering Committee with membership drawn from those countries that have agreed to provide support (Austria, Belgium, Denmark, Finland, France, Norway, Portugal, Sweden, Switzerland and UK) and from the mining industry. At its first meeting on 3 April, the Steering Committee set up project working groups to define the scientific problems on which to focus in each of the five main projects and to initiate the scientific activites needed to address them.
The Minerals Industry Research Organisation, MIRO, was asked for help in setting up this database. Following two productive meetings a strategy has been formulated and MIRO has every hope of funding the project for GEODE and setting up and managing the database scheme early in 1999. Care is being taken to ensure that it will be fully compatible with other database schemes, in particular the GIEXS scheme of EuroGeoSurveys. GEODE is also making efforts to publicise its activites through the establishment of a website (http://www.gl.rhbnc.ac.uk/geode/) which includes an open invitation to all interested scientists to become involved, and would be delighted to hear from SGA members. Symposia are being organised during the European Union of Geosciences Assembly in Strasbourg, 28 March-1 April 1999 and the SGA-IAGOD meeting to be held in London 22-25 August 1999, which will include a GEODE session on "Geodynamics and ore deposit provinces". Further workshops relating to specific GEODE projects are also planned for 1999 in order to involve the broader scientific community, particularly younger researchers. If you are interested in GEODE please contact the Steering Committee chairman Professor Derek Blundell (d.blundell@gl.rhbnc.ac.uk), or any of the Working Group convenors.

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