Using information from SGU

The geological information held by SGU is generally basic in nature and may require further processing to be of maximum benefit. Often several different kinds of information can be combined. Our Customer Services will be pleased to help you find the information you need.

Bedrock databases

Information on bedrock geology provides a basis for exploration – for metal ores, industrial minerals, hydrocarbons, and rocks suitable, for example, for monumental stonework or as aggregates for road and railway construction or for making concrete. Bedrock information is also important in the planning of construction, civil engineering and geothermal energy projects, and in the environmental sphere.

Quaternary geology databases

Information on the distribution, structure and properties of Quaternary (superficial) deposits is used, for example, in physical planning, to locate gravel and sand (aggregates) of the right quality, and to assess the availability of groundwater, fuel peat and various minerals. It is also important in agriculture and forestry and in environment protection, among other things as a basis for assessing the risk of dispersion of contaminants in soil and groundwater.

Hydrogeological databases

SGU’s information on groundwater is an important input into the planning of public water supplies. It is also one of the key factors in achieving Sweden’s environmental quality objective Good-Quality Groundwater, as well as having a part to play in meeting the requirements of the EU’s Water Framework Directive. In addition, groundwater information is used in the area of land use and physical planning in general, e.g. as a basis for environmental impact assessments and for action programmes to protect groundwater.

Marine geological databases

SGU is surveying and mapping the seabed in Sweden’s territorial waters and exclusive economic zone (EEZ). The purpose of marine geology mapping is mainly to produce data for the planning of and decisions on protection and use of sea bottoms. The information is used, inter alia, in connection with the planning of marine construction works and environmental monitoring. It also provides important input for biological surveys, for the fisheries industry and for the Armed Forces.

Geochemical databases

Biogeochemistry

The purpose of SGU’s biogeochemical mapping is to map both natural occurrences of various metals in the environment and concentrations of metals that are released as a result of human activities. Analyses of plant roots and aquatic mosses in streams in a given area provide data on the variations in concentrations of substances, such as heavy metals in natural waters (1 sample per 6–7 km 2).

The magnitude of the concentrations, i.e. the amount of a certain substance that leaks into watercourses with the groundwater and is then absorbed by plants, depends on the quantity of metals occurring naturally in the soils and bedrock in the area and on the quantity of metals in the area that have been spread as a result of air pollution or other emissions.

The results of these studies are used mainly for environmental monitoring, e.g. for identifying areas with high loads, natural or anthropogeneous, of environmentally harmful substances such as cadmium and mercury, as well as in connection with prospecting for ores and minerals or identification of areas with low concentrations of trace elements etc. that are important to humans and animals.

Soil geochemistry

The purpose of SGU’s soil chemical mapping activities is to produce data on the natural occurrence of metals and other substances in a given area. Data is obtained on the natural occurrence of more than 30 elements in soils, especially in forest-covered moraines, and on soil acidity (pH).

This information is used, inter alia, for the purposes of environmental monitoring, soil research, forestry, mineral exploration, municipal planning and medical research.

Geochemistry open data base download instruction (in Swedish)

Geochemical Atlas of Sweden (pdf, in Swedish)

Geophysical databases

Gravity

The information in the gravity database is used for determining the distribution of different rock types, for mapping ore-bearing structures, and for locating major aquifers and suitable areas for geothermic energy production. The data is also used in various geodetic applications, for navigation and positioning purposes, and for calibrating scales and pressure sensors.

SGU initiated systematical gravity measurements in the late 1950s in conjunction with the documentation of iron ores in northern Sweden. The regional, nationwide measurements were started in the middle of the 1960s, serving primarily as support for SGU's bedrock mapping activities. Nowadays gravity measurements are mainly carried out along roads by car and, in areas with sparse road coverage, by snowmobile or helicopter.

The gravity measurements in the Gulf of Bothnia and the Bothnian Sea were carried out on the ice, mainly in the 1970s and parts of the 1980s. In the late 1990s, parts of the Bothnian Sea and a few sections of the Baltic Sea, Kattegat and Skagerrak were measured from ships. In 1999, the Baltic Sea and the lakes Vänern and Vättern were measured from aircrafts at intervals of about 15 km. SGU collaborated with several Nordic and Baltic institutions during these measurement campaigns.

The digital gravity data includes the observed g-value, free-air and Bouguer anomalies and, for a large part of the material, terrain corrections. In total, the database contains 320,000 measurement points, 132,000 of which are dense measurements acquired over exploration targets mainly in the 1970s and 1980s. The database includes some measurements made by other organizations, for example the National Land Survey.

Magnetic field

Airborne magnetic data, which provide information about the structural features of the bedrock irrespective of soil and water depth, are used mainly in connection with geological mapping. This is very important, since only a few per cent of Sweden’s bedrock is exposed, the rest being covered by soil and water.

Originally, the purpose of SGU’s airborne measurements of the geomagnetic field, which have been carried out since 1960, was to explore for iron ore. Apart from SGU, the main users of the information today are prospectors and consultants in the geoindustry. Local magnetic deviation maps, especially for the Armed Forces, are also based on these measurements.

Nowadays the measurements are made at an altitude of 60 metres (previously, until 1994, the altitude was 30 metres) and the aircraft fly in straight lines from east to west or north to south at intervals of 200 metres. The distance between the measurement points along each line is about 18 metres (until 1994 it was 40 metres). Satellite navigators and radar altimeters are used to ensure correct positioning. Various magnetometers have been used over the years. Since 1995, an extremely accurate caesium magnetometer has been in use. The database includes some measurements made by other organizations.

The data are supplied in two resolutions: 200 x 200 metres for general information and the original resolution of 200 x 40 metres or denser.

Gamma radiation

Gamma radiation data, i.e. data on radioactive ionizing radiation, are used mainly for bedrock surveys, for radon studies and in efforts to ensure a safe radiation environment. Measuring gamma radiation makes it possible to calculate the concentrations of naturally occurring radioactive isotopes of potassium, uranium and thorium in the ground. From 1986 onwards it has also been possible to calculate the caesium contamination. Apart from SGU and the National Radiation Protection Institute, the users include consultants in the geo and radon industries, prospectors and municipalities and county administrative boards.

SGU has made airborne gamma spectrometric measurements ever since 1967. The measurements were originally made in connection with uranium exploration.

Nowadays the measurements are made at an altitude of 60 metres (previously, until 1994, the altitude was 30 metres) and the aircraft fly in straight lines from east to west or north to south at intervals of 200 metres. The distance between the measurement points along each line is about 18 metres (until1994 it was 40 metres). Satellite navigators and radar altimeters are used to ensure correct positioning. The database includes some measurements made by other organizations.

The data are supplied in two resolutions: 200 x 200 metres for general information and the original resolution of 200 x 40 metres or denser.

Electromagnetic fields

Electromagnetic data are used mainly in connection with bedrock mapping, hydrogeological mapping and exploration. The measurements record secondary electromagnetic fields produced by induction, for example in conductive minerals or large bedrock fault zones. Interpretation of electromagnetic data provides information about the structural features and weakness zones in the bedrock and about ground conductivity.

SGU has carried out airborne electromagnetic measurements since 1972. The original purpose of these airborne measurements was to explore for minerals, and they provided important data input.

Nowadays the measurements are made at an altitude of 60 metres (previously, until 1994, the altitude was 30 metres) and the aircraft fly in straight lines from east to west or north to south at intervals of 200 metres. The distance between the measurement points along each line is about 18 metres (until 1994 it was 40 metres). Satellite navigators and radar altimeters are used to ensure correct positioning. VLF transmitters, including one in Rugby, England, are used for the measurements. Since 1995 two transmitters have been used simultaneously. The database includes some Slingram and VLF data based on measurements made by other organizations.

Petrophysics

The petrophysics database contains information on density and magnetic properties of rocks and content of potassium, thorium and uranium. Altogether, about 75,000 samples with specified coordinates have been taken and about 5,900 outcrop gamma radiation measurements have been made.