Lito-project
Project Leader: Trond Slagstad
Mapping
In order to ensure good geographical coverage, we have subdivided Norway into c. 3800 9*9 km squares. One sample is collected within each square, and where possible, the number of samples from units on the 1:250,000-scale maps reflect the units' areal extent. Sample localities are predetermined by a geologist.
Sampling
The samples are collected as 35 mm diameter, 3-meter long cores by diamond drilling in order to ensure fresh, unweathered samples. On a normal day, 4 samples are collected.
Logging
After the cores have been drilled they are transported to NGU where they are logged, photographed and scanned for magnetic susceptibility and total gamma radiation. The visual description ("logging") is used as the basis for determining which part of the core to extract for analysis. Even though the main purpose of the LITO project is to determine the rocks' chemical composition, we also determine other parameters, in particular density, magnetic susceptibility, resistivity and thermal conductivity. Sample intervals are marked and photographed for documentation. The photographs also yield valuable information about the heterogeneity in the cores (in general Norwegian bedrock is rather heterogeneous). The degree of fracturing in the rocks is also registered, providing valuable information about hydrogeological properties.
Analyses
The chemical analyses are carried out at NGU's laboratory, and include XRF, LA–ICP–MS, ICP-AES, and atomic absorption (more here). Every fifteenth analysis is analysed in duplicate, and every tenth sample is a standard with known composition. This is done to ensure identification of possible errors during the analytical work, for example related to drift in the instruments. The result is an extensive dataset of chemical and petrophysical properties that will cover the entire Norwegian mainland.