November 2012    Print this article

New geophysical surveys now available in SIGEOM

Rachid Intissar and Isabelle D'Amours, MRN

The Ministère des Ressources naturelles (MRN) carried out large-scale airborne geophysical surveys in several geological provinces during the 2011-2012 year. The surveys covered 415,766 linear kilometres and a total surface area of about 99,052 km2. The ultimate goal for these high-resolution surveys is to support geological mapping projects, whether those of the MRN or of private companies, and to promote mineral exploration. The collected data is also used to identify targets of interest, which stimulates investment from the private sector for exploration.

Since early 2012, clients have been able to access the new data described below using the SIGEOM database.

Click on image to enlarge

Rivière Koksoak area and Lac Lemoyne area

These two airborne magnetic and gamma ray spectrometry surveys cover part of the Labrador Trough and the Core Zone of the southeast Churchill Province. The data are published in DP 2011-06 and DP 2011-07. The processing and preliminary interpretation of the spectrometry data identified ten exploration targets (PRO 2012-01 available at the “E-SIGEOM Examine” tool).

Lac Evans area

This airborne survey was flown over the west part of the Opatica Subprovince and the south part of the Nemiscau Subprovince in the Baie-James region. The survey, which extends over 33 map sheets at 1:50,000 and is published in DP 2012-01, completes the high-resolution magnetic coverage of the Baie-James region and the Abitibi Subprovince.

Malartic area

This helicopter-borne high-resolution magnetic survey was flown over the Malartic area of the Abitibi Subprovince. It covers map sheet 32D01 and part of map sheet 32C04. This magnetic survey, carried out at a nominal terrain clearance of 40 m (where allowed) and a flight line spacing of 100 m, provides high-quality data for a region where the MRN is carrying out a geological and structural map revision at 1:20,000 scale. The survey is part of a collaborative effort between the Bureau d’exploration géologique du Québec (BEGQ), the Geological Survey of Canada (GSC), the Canadian Mining Innovation Council (CMIC), and a number of mining companies.

Mistastin Batholith and Lac Brisson area

As part of the Targeted Geoscience Initiative 4 (TGI4) program, Natural Resources Canada completed two surveys that are now available through SIGEOM:

The data for both Natural Resources Canada surveys are also available from the Geological Survey of Newfoundland and Labrador or the Geoscience Data Repository of the Earth Sciences Sector of Natural Resources Canada.

Upcoming publications are discussed below.

Manic-Outardes area and Lac Sainte-Anne area

These two new aeromagnetic surveys flown south of the Manicouagan Reservoir in the geological Grenville Province were completed in the spring of 2012. The surveys will be published as DP 2012-02 and DP 2012-03 during the Québec Mines convention in November 2012. They support ongoing 1:50,000 geological mapping and provide a high-quality inventory of geophysical data for a region containing several underexplored areas. Other surveys are scheduled elsewhere for late 2012 and in 2013 in order to continue acquiring geophysical data throughout the Grenville Province.

The images for these surveys, as well as other high-resolution surveys carried out during recent years, will be available in Geotif format starting November 26, 2012.

Lac Romanet area and Rivière à la Baleine area

As part of ongoing efforts to provide complete coverage of the Churchill Province, two other magnetic and spectrometry surveys were carried out during the summer of 2012 and should be published during the PDAC convention in March 2013.

A preliminary report prepared by Thomas Clark and Isabelle D’Amours, titled “Interprétations structurales et métallogéniques dans la Fosse du Labrador d’après les cartes magnétique et spectrométrique”, will be released during the Québec Mines convention. The report, accompanied by compilation airborne geophysics maps at 1:500,000, will provide observations and interpretations derived from a preliminary examination of data recently made available, and will attempt to incorporate them into the current tectonostratigraphic model for the Labrador Trough. The cited examples will focus on the shape and nature of the major faults and regional fold systems, the link between deformation in the Trough and that of the hinterland, the distribution of iron formations, and the possible causes of spectrometric anomalies. The report will be released as RP 2012-02. Some of the interpretive results will be presented during a talk to be given at the Québec Mines 2012 convention, titled “Geophysical surveys in the Labrador Trough and Churchill Province: results and preliminary interpretation”, on Tuesday, November 27, at 3:10 p.m.

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