Geological mapping

Geological mapping in Mozambique. Photo:

Geologic map information is helpful in natural resources development; infrastructure development, including land-use planning; environmental management; natural hazard identification; and scientific research and education. Regional geologic maps can be used to identify geological risks, promote safe engineering, help in decision-making and improve infrastructure planning. While the true value of mapping to society and the economy is hard to quantify, it is clearly many times greater than the production costs.

Geologic mapping generates essential information on the distribution, composition, structure, origin of rock units and their evolution in space and time. They can be presented in printed form or as thematic digital datasets that are visualized as three-dimensional block models. Together with the results of geochemical and geophysical investigations, geological maps provide a sound basis for assessment of mineral resource potential, construction materials and energy and water resources as well as for infrastructure and land use planning. The extensive and validated geodata on which maps are based form an invaluable platform for developing scientific hypotheses and models. Map databases facilitate integration of geology with an almost infinite variety of spatially referenced datasets from other areas, including socio-economic data, and thus encourage a wide range of multidisciplinary studies.

GTK mapping capabilities encompass the entire process from fieldwork and data capture to final map production. Modern fieldwork and data management is supported by global positioning (GPS), weatherproof PCs and geographic information systems (GIS) that enable electronic positioning, storage, display, query and analysis of geologic observations. Map synthesis and interpretation is routinely enhanced by access to various ground-based geophysical and geochemical survey data, remote sensing data such as orthophotos, hyperspectral and airborne geophysical data and Landsat, Radarsat, Aster and newer types of satellite images and, of course, chemical, mineralogical and isotopic analyses of collected samples. In certain complex situations, bedrock drilling may also be undertaken to obtain critical information. Versatile commercially available analytical software, such as ArcInfo™ is used to combine and analyze different sets of map databases in an appropriate format on-line. To provide the public with similar access, but without the need for costly software, special web browsers have been developed.

From traditional maps to 3D spatial mapping

At GTK, all geological mapping information and other data sets are digitally managed and archived, using ArcGis, ArcSDE and relational databases. Digital data collection in the field supported by experienced map-production personnel enables high-quality map production. GTK also assist clients in visualization of geological data in combination with other datasets.

Efficient delivery of and easy on-line access to geological maps and databases is crucial for both professional users and the general public. Technical solutions for a completely updated information geodata management system have been designed and implemented under GTK’s GeoKernel project. The developed system covers all aspects of the information production process from fieldwork through map production and dissemination. GTK provides an interactive Active Map Explorer service at http://geomaps2.gtk.fi/activemap/ that allows the user to view geologic maps, submit queries and view results.

GTK geological mapping capabilities have been developed over more than a century, including the following milestones:

Systematic regional mapping of both the Precambrian crystalline basement and Quarternary deposits in Finland.
Thematic mapping projects based on e.g. economic geology, metamorphic grade, environmentally sensitive areas and urban geology.
Structural modelling of the North-European Shield by means of deep seismic reflection sounding traverses.
International mapping and map production projects such as the 1:2,000,000 Geological Map of the Fennoscandian Shield; Geological Map of Europe; and the 1:1,000,000 thematic series of the northern and central parts of the Nordic countries (Nord-Kalot and Mid-Norden).
Geological mapping and mineral resources consulting projects in Australia, Kenya, Tanzania, Namibia and Mozambique.
Over two decades of work with GIS and digital methods in map production.

Quality-controlled, standardized mapping observations are the basis for detailed, reliable maps to facilitate informed decision making by users. The methods and procedures applied in mapping are dependent on the scale and purpose of the study. In the production of regional geological maps, traditional geological field mapping is supported by modern map production to integrate the existing geological knowledge with new geophysical information, remote sensing data, Digital Elevation Model (DEM) and other relevant data. Integration of modern isotopic data with major, minor and trace element geochemistry and mineralogical analysis assists the mapping geologist in understanding the geological history and stratigraphy of the study area.