Automated extraction of orientation and stratigraphic thickness from geological maps

Abstract

Geological maps are available for almost every region of the world and, therefore, represent the most commonly used source of information for earth scientists. Advances in computing power and the availability of digital elevation data have opened new possibilities to automatically extract quantitative information from geological maps, especially in regions with topographic relief and good bedrock exposure. We present an innovative approach to automatically extract orientation (dip direction/dip) and stratigraphic thickness from a 1:25′000 geological map vector data set of the Swiss Alps. The approach allows a rapid spatial overview on the orientation and thickness of a given geological unit over large areas. Key improvements of the approach with respect to commonly used 3D modelling approaches are its objectivity, rapidity and the possibility to classify and/or filter orientation and thickness model output after five numeric reliability parameters. The approach is designed to support authorities and the industry in performing a rapid screening of a given region and to early identify promising areas for potential mineral extraction projects. Large-scale spatial overviews on the orientation and thickness of geological units are of large interest in many other disciplines such as tectonic and stratigraphic reconstruction, hydrogeological or geotechnical analyses. Therefore, the approach will be widely applicable also beyond the evaluation of potential mineral resources.