Thin section analysis of microstructures of till boulders compared to Los Angeles Values

The project is associated with a larger project, financed by Formas. The aim is to study the physical composition of the till and see if and how there is a couple to bedrock properties. The project studies till from all different aspects. Two test areas associated with rock quarries have been studied in detail, one at Olunda near Uppsala, and one at Bäckseda near Vetlanda. Several geophysical tests have been made over a test area of till at each site. This includes georadar, resistivity, magnetic susceptibility, VLF and seismic. The total size distribution and lithological composition of the clasts has been studied at each site, from either sections or sample pits. The size distribution and the composition of the clasts are determined.
The aim of this master’s project is to correlate microstructure in bedrock to the Los Angeles Value. In engineering the Los Angeles, LA, Value is means for documenting the quality of the rock with respect to usage as aggregate material. If we want to open a rock quarry we want to insure that the rock mass in the proposed quarry will produce good quality aggregates. In order to determine this samples of the bedrock that crop out in the area are taken and tested. However, in Sweden till covers a large portion of the bedrock and our samples may only be located in the better quality rock material, high points that crop out. Poorer quality material can be hidden by till in the depressions. We cannot take samples for LA testing.
The aim of this project is to compare how the LA value of till boulders, in the area around an existing rock quarry, corresponds to the LA value of the rock mass in the quarry, and to study the rocks in thin section to see how microstructures in the rock mass correlate to the LA value.
The rock material has been collected from the two quarries, in association to the large research project. That which remains is to carry out LA tests and thin section analysis on the till boulder samples and bedrock samples.
The student requires good knowledge in petrography and thin section analysis.

The advisor of the project is Docent Joanne Fernlund. The thin section analysis will be done in association with Jan Erik Lindqvist at Swedish National Testing and Research Institute (SP).