Towards a better understanding of the Superior Province

Robert Marquis
Géologie Québec

Figure 1 : The Superior Province is a vast region whose specific geological characteristics make it especially attractive for mineral exploration. This map of the Superior Province shows the main subdivisions, which include the Abitibi sub-province, the La Grande sub-province and the Grenville Front.

The Superior Province is a vast region whose specific geological characteristics make it especially attractive for mineral exploration (Figure 1). It contains large areas of ancient volcanic rock over 2,700,000,000 years old likely to contain gold, copper and zinc deposits, magmatic rock rich in nickel and platinum, Algoma-type iron formations, and diamond-bearing kimberlite bodies from a more recent period than the volcanic rock.

This year, Québec Exploration 2004 will include a technical session that will look specifically at the Superior Province. Speakers from Québec, Ontario and Manitoba will discuss the geological evolution, detailed internal structure and mineral potential of this geological province. The traditional focus on Québec and Ontario will be extended to include Manitoba, offering participants a technical session that will cover the whole of the Superior Province. The topics covered will include different types of mineralization, especially orogenic gold deposits, internal subdivisions and the nature of contact with adjacent geological provinces.

Historical background

Québec and Ontario have worked together to disseminate geological knowledge about the Superior Province for over 20 years. In 1984, the first geological map covering the entire Abitibi greenstone belt to a scale of 1/500 000 was published jointly by the Québec department of Energy and Resources and the Ontario Geological Survey (OGS). At the time, the focus was on the Abitibi greenstone belt (Figure 2) because of its high concentration of rich metal deposits, in production since the early 20^th century.

Figure 2 : The Abitibi greenstone belt is especially important from an economic point of view, because of its high concentration of rich metal deposits, in production since the early 20th century. This photo shows the types of transportation used to gain access to the remotest areas.

In 2000, Québec and Ontario also collaborated to present a special technical session devoted to the Abitibi greenstone belt and adjacent areas in the Superior Province. This technical session was given in Québec as part of the annual information seminar on geological research. Later, fourteen scientific papers derived from the technical sessionwere published in a special issue of the journal Precambrian Research for 2002, co-edited by W. U. Mueller (Université du Québec à Chicoutimi), R. Marquis (Ministère des Ressources naturelles de la Faune et des Parcs) and P. Thurston (OGS).

In Québec, between 1995 and 2002, a detailed mapping program at a scale of 1/50 000 was carried out in the Baie James area (Figures 3 and 4) to improve the cartographical, geochronological and metallogenic data available, and to create a new overview for the sectors of the La Grande and Eastmain rivers, two regions of the Superior Province with strong mineral potential.

Figure 3 : A geologist crosses a gigantic rocky outcrop in the Baie James area, in the promising exploration sector of the Rivière Eastmain.	Figure 4 : In the Baie James area, the detailed 1/50 000 mapping program required the sampling and analysis of many different rock samples, carefully selected for their geological characteristics and economic potential.

During the same period, between 1998 and 2003, Québec conducted an ambitious mapping program of the eastern section of the Superior Province, to the north of Baie James. The program, known as “Projet Grand Nord”, led to completion of map coverage at a scale of 1/250 000 and the initial metallogenic reconnaissance of northern part of Québec (Figures 5 and 6). In addition to opening up new areas for mineral exploration, this extensive program to acquire new knowledge allowed considerable progress to be made in terms of the geological understanding of northern lands. Rocks among the oldest in the world were discovered along the Hudson Bay shoreline, and several thematic projects were conducted in partnership with the Université du Québec à Montréal, McGill University, Simon Fraser University and the Geological Survey of Canada. The scope and complexity of the program mobilized practically all the human and financial resources of Géologie Québec. Currently, several geologists are still working to assemble all the information gathered during the project.

Figure 5 :The “Projet Grand Nord” led to completion of map coverage at a scale of 1/250 000 and the initial metallogenic reconnaissance of Nord-du-Québec. In this photo, one of the department’s geologists carries out observations in the field, to the north of the tree line.	Figure 6 : The “Projet Grand Nord” opened up new areas for mineral exploration. This photo shows a temporary summer camp, set up for 10 weeks to house an 18 member geological team.

Figure 7 : In the Chibougamau sector, the current program of work is intended to gather more precise information about the contact between the Superior Province and the Grenville Province. In this photo, a group of geologists discusses the economic potential of the outcrop in the foreground.

A continually renewed approach

In 2003, detailed work at a scale of 1/50 000 was carried out in the Chibougamau sector (Figure 7), giving a more precise view of the t pe of contact between the southern edge of the Superior Province and the Grenville Province, an ancient, highly eroded mountain range that brings to the surface rocks formed deep in the earth’s crust.

In the Abitibi greenstone belt, in both Québec and Ontario, current work involves compiling the data needed to update the 1984 Ontario-Québec map and completing targeted cartographical projects and highly detailed metallogenic overviews of various mining camps (Figure 8). In Québec, as part of the metallogenic overviews, special attention is paid to integrating public databases, allowing 3D modelling in partnership with the Université du Québec en Abitibi-Témiscamingue that proves extremely useful in determining new exploration targets.

Figure 8 : In the Abitibi greenstone belt, highly detailed metallogenic overviews integrate public databases containing information from a number of mining camps and 3D modelling, especially useful for determining new exploration targets. A young geologist from the department shows a detailed geological map to colleagues from the mining industry.

In addition to a technical session to look specifically at the Superior Province, Québec Exploration 2004 will include two multimedia workshops to present results from detailed surveys carried out by MRNFP geologists. The workshops will be conducted by the MRNFP geologists responsible for each project. The first workshop will examine recent discoveries in the Rouyn-Noranda region, where the Blake River Group is under intensive scrutiny to identify new sources of copper ore. The second workshop will deal with the Chibougamau area, and more specifically will look at mineral potential on the Grenville Front, the boundary between the Superior Province and the younger Grenville Province.

You are warmly invited to attend these interactive workshops.

Références

1994, Géologie du Québec, Les publications du Québec, pages 7 to 46.

2002, Evolution of the Archean Greenstone Belt and adjacent terranes: New Insights from Geochronology, Geochemistry, Structure and Facies Analysis, Precambrian Research, Special Issue, volume 115, 371 p.

MERQ-OGS, 1983, Carte lithostratigraphique de la sous-province de l’Abitibi : ministère de l’Énergie et des Ressources du Québec/Ontario Geological Survey: 1:500 000, catalogué "DV83-16" à Québec et "Map 2484" en Ontario.