THE GEOLOGICAL SURVEY OF SWEDEN The Geological Survey of Sweden (SGU), established in 1858, is the national central government agency responsible for the investigation of the geology of Sweden. Its main tasks are to prepare and issue geological maps, maintain digital data bases and to provide up-to-date geological, geophysical, geochemical and sedimentological data prognoses and information regarding resources such as groundwater, sand and gravel, ores and minerals. SGU grants licences for the prospecting of sand, gravel, or stone within the public waters of the Swedish EEZ at the same time as it must ensure compliance with the legal regulations and conditions for such licences. SGU is the principal authority for the mine inspectores in Sweden. The survey is run from the head office in Uppsala and three branch offices in Lund, Göteborg and Malå respectively. The survey is organized in six geological and two administrative divisions. The Division of Marine Geology, has a permanent staff of twelve persons (seven marine geologists, one computer-system engineer, two sea captains and two chiefs). The annual budget for the marine mapping programme is about 1.4 million ECU in 1998 (including the capital costs of the survey vessel). The division has been carrying out work in the regional mapping of the seas around Sweden and elsewhere since the start in the beginning of the 1970s. The marine geological mapping programme also comprises a special geochemical subprogramme concentrating on natural and anthropogenic substances (c. 60 inorganic elements, i.a. heavy metals and c. 50 organic micropollutants, i.a. PCBs, PAHs and DDTs are studied). Within the Swedish EEZ some 16 000 km of shallow seismic and subbottom profiler; and some 13 000 km of side scan sonar track have been acquired and about 7 000 sea-bed surface and core samples collected by SGU. For operation at sea SGU has a twin-hull, sandwich constructed survey vessel, S/V Ocean Surveyor (Fig. 1), of 509 brt, 38 m long and 12 m wide. The vessel has 6 winches A-frame, moon-pool, sediment laboratory, photo laboratory and a special survey-room for data processing. The division and vessel are equipped as follows (Fig. 2): dynamic positioning system and HPR doppler log satellite navigator, DGPS, Syledis positioning systems including survey computer seven work-stations and 14 PC shallow seismic systems (boomer, sparker, sleve gun) 50, 100, 500 kHz and 100 khz chirp side scan sonars 3.5/7 kHz and 8 kHz chirp pingers 33/200 kHz echo sounders CTD-sond including processing software vibro-hammer corer (6 m) piston corers (3/6 m) gemini corer and gravity corers including subsampling devices grabs under-water video, sea-floor camera radiometer including processing software The capacity for submarine investigations has led to SGU being contracted to carry out a large number of commission projects in connection with, e.g. harbour and channel constructions, tunneling, laying of cables, search for dumped ammunition and various environmental monitorings based on sediment studies. A number of research projects have been carried out by people at the Division of Marine Geology and several projects are in progress, many in cooperation with other agencies and universities. Currently Sweden has mapped 15 % of the Swedish EEZ. The results are published in five maps from the Sounds at a scale of 1:50 000 (SGU Rapporter & Meddelanden, no. 13), three maps from the northern Gotland area in the Baltic Sea (SGU Serie Am, no. 1-3), three maps from the Kattegat (SGU Serie Am, no 4-6) and one map from the Stockhom Arcipelago (SGU Serie Am 7) at a scale of 1:100 000. Field work has been completed within four map areas in the Stockholm Archipelago and within three map areas in the south-western Baltic Sea south of Scania. An outline map of the solid geology of the Swedish EEZ at a scale of 1:1 000 000 (SGU Rapporter & Meddelanden, no 47) was published in 1986. In cooperation with the National Forest and Nature Agency of Denmark and the Geological Survey of Denmark a map at a scale of 1:500 000 showing the bottom sediments around Denmark and western Sweden was published in 1992 (SGU Serie Ba, no 48). In cooperation with the Geological Survey of Lithuania a bottom sediment map and a bathymetric map over the Central Baltic Sea at a scale of 1:500 000 were published in 1998. In the National Atlas of Sweden outline sedimentary and bedrock maps at a scale of 1:2 500 000 over the Baltic Sea, the Kattegat and the Skagerrak were published in 1992 (volume "Sea and Coast") and 1994 (volume "Geology"). Fig. 1. The survey vessel "Ocean Surveyor" belonging to the Geological Survey of Sweden. Fig. 2. Equipment of the survey vessel "Ocean Surveyor" for mapping of the seabed. Equipment of the survey vessel "Ocean Surveyor" for mapping of the seabed Positioning systems 1. Satellite positioning system 2. Differential GPS 3. Hydroacoustic positioning system Hydroacoustic survey methods 4. Seismic sound source 5. Hydrophone 6. Subbottom profiler 7. Echo-sounder 8. Side scanning sonar (i.a. chirp) Sediment sampling methods 9. Gravity corer 10. Grab sampler and box corer respectively 11. Vibrohammer corer 12. Piston corer Observation systems 13. Scuba diver 14. Underwater video-camera 15. Remote Operating Vessel (ROV) 16. CTD sond Ingemar Cato, PhD Geological Survey of Sweden Division of Marine Geology Box 670 S-751 28 Uppsala, Sweden SGU Website: http://www.sgu.se