WORK METHOD

Surveys Conducted in Isolated Areas with Some Road Access

Geological mapping is carried out by working teams consisting of a geologist and a geological assistant. Access to most of the territory is by helicopter. Nonetheless, vehicules are used locally where roads cross the study area. Teams are deposited at their point of entry from which they make 5 to 14 km-long line transects. Spacing between the lines and their length, as well as spacing between described outcrops depend on the mapping scale, thickness of surface deposits, density of vegetation, topography, outcrop extension, its quality of exposure and the geological complexity of the area. The shores and islands of large bodies of water and rivers are routinely mapped by boat. Areas difficult to access with low outcrop density are also covered by helicopter, spot stops or the“leapfrog” technique.

Outcrops are described using electronic tablets to capture field data in the “Geofiches” module (see MB 98-05 and DV 2013-07 documents). Data is then integrated into the SIGÉOM database. To better characterize geological units, representative samples are analyzed using the following techniques:

The stratigraphic nomenclature of the mapped area meets the standards of the North American Stratigraphic Code (DV 86-02, MNR, 1986; North American Commission on Stratigraphic Nomenclature, 2005; Easton, 2009) and the already-established nomenclature. Units were defined in terms of rock composition, age, cross-cutting relationships, structures and textures, and regional distribution.

23 octobre 2018