, 11 n Special Publicatio y Geology for SocietyGeology for SurveyGeological of Norwa Trond Slagstad (ed.) Slagstad (ed.) Trond Geology for Society Geological Survey of Norway Special Publication, 11 Trond Slagstad (ed.) Geological Survey of Norway Special Publication, 11 The NGU Special Publication series comprises consecutively numbered volumes containing papers and proceedings from national and international symposia or meetings dealing with Norwegian and international geology, geophysics and geochemistry; excursion guides from such symposia; and in some cases papers of particular value to the international geosciences community, or collections of thematic articles. The language of the Special Publication series is English. Editor: Trond Slagstad ©2008 Norges geologiske undersøkelse Published by Norges geologiske undersøkelse (Geological Survey of Norway) NO–7491 Norway All Rights reserved ISSN: 0801–5961 ISBN: 978-82-7385-130-7 Design and print: Skipnes kommunikasjon 103851/0508 Cover illustration: Miners working 295 metres below the surface in the silver mines in Kongsberg in 1912. Photo: Mimi Johnson. Contents Introduction Trond Slagstad (ed.) ....................................................................................................................................................................................................... 3 National treasure of global significance. Dimension-stone deposits in larvikite, Oslo igneous province, Norway Tom Heldal, Idunn Kjølle, Gurli B. Meyer and Sven Dahlgren ................................................................................................... 5 Geology of the soapstone deposits of the Linnajavri area, Hamarøy, Nordland, north Norwegian Caledonides—Norway’s largest reserves of soapstone Ingvar Lindahl and Lars Petter Nilsson .......................................................................................................................................................... 19 Aggregates in Norway—Properties defining the quality of sand, gravel and hard rock for use as aggregate for building purposes Eyolf Erichsen, Arnhild Ulvik, Knut Wolden and Peer-Richard Neeb ...................................................................................... 37 From Hyllestad to Selbu: Norwegian millstone quarrying through 1300 years Tor Grenne, Tom Heldal, Gurli B. Meyer and Elizabeth G. Bloxam ........................................................................................ 47 Groundwater monitoring and modelling from an archaeological perspective: possibilities and challenges Hans de Beer and Henning Matthiesen ........................................................................................................................................................... 67 Global geochemical mapping and sediment-associated flux of major world rivers Jim Bogen and Rolf Tore Ottesen .......................................................................................................................................................................... 83 Ground-Source Heat Pumps and Underground Thermal Energy Storage— Energy for the future Kirsti Midttømme, David Banks, Randi Kalskin Ramstad, Ola M. Sæther and Helge Skarphagen .................. 93 Factors influencing shallow (< 1000 m depth) temperatures and their significance for extraction of ground-source heat Trond Slagstad, Kirsti Midttømme, Randi Kalskin Ramstad and Dag Slagstad ............................................................... 99 Sediment fluxes and sediment budget in Latnjavagge and the potential of applying unified methods for integrating investigations on sediment fluxes and budgets in cold-environment catchments Achim A. Beylich .............................................................................................................................................................................................................. 111 Airborne gamma-ray spectrometer mapping for relating indoor radon activity concentrations to geological parameters in the Fen region, southeast Norway Björn Henning Heincke, Mark Smethurst, Arne Bjørlykke, Sven Dahlgren, Jan Steinar Rønning and John Olav Mogaard ............................................................................................................................................................................................. 131 Testing the performance of a recent radon-hazard evaluation in the municipality of Gran, eastern Norway Mark A. Smethurst, Aud Venke Sundal, Terje Strand and Bernard Bingen ......................................................................... 145 Introduction Geology has always had a significant impact on human society and the way it has evolved. The names of important epochs in this evolution, such as the Bronze Age, Iron Age, Oil Age—not to mention the Stone Age—reflect geology’s significance in shaping society. However, the days when one could strike it rich by drilling a well at random or accidentally stumble across a Mother Lode are all but gone, and discovering, utilising and managing geological resources and hazards today require significant knowledge about the underlying geological processes. This volume of NGU Special Publication presents some of the ongoing research at the Geological Survey of Norway and shows how geology and geological knowledge influence many areas of society. The global demand for geological resources is on the rise, and knowing where to look for these resources is becoming increasingly more important. In addition, quantifying these resources is vital to ensure present-day as well as future supplies. As society and technology evolve (cf., the Stone Age-, Bronze Age-, Iron Age- progression) so does the demand for geological resources. A sagacious assessment of geological resources therefore requires a broad, research-based approach. Although surprising to many, we as geologists are well aware that Earth is a dynamic, ever-changing planet. As Earth’s population grows and formerly uninhabited areas are inhabited, understanding the effects of these changes on the land on which we live becomes increasingly important. Furthermore, managing and sustaining the environment that today’s and future societies depend on require understanding of how our actions affect our surroundings both on a local and global scale. As societies have expanded and continue to expand into unchartered territories, knowing what hazards lie ahead—not to mention above and below—requires insight into geology and geological processes. Rather than highlighting a particular topic, which is often the case with Special Publications, the purpose of this volume is to emphasise the span of what we consider to be ‘geology’ and show how these diverse topics come together under the common topic ‘Geology for Society’—the motto of the Geological Survey of Norway. Although 150 years old and counting, the arrows continue to point up and out with regard to society’s need and demand for geological knowledge. Trond Slagstad Editor National treasure of global significance. Dimension-stone deposits in larvikite, Oslo igneous province, Norway Tom Heldal1, Idunn Kjølle2, Gurli B. Meyer1 and Sven Dahlgren3 1Geological Survey of Norway (NGU), 7491 Trondheim, Norway. 2Directorate of mining, 7491 Trondheim, Norway. 3Geological advisor, Buskerud, Telemark and Vestfold, Fylkeshuset, 3126 Tønsberg, Norway. E-mail: [email protected] Larvikite has for more than a hundred years been appreciated as one of the world’s most attractive dimension stones, and at present, its production and use is more extensive than ever. The main reason for the continuous success of larvikite on the world market is the blue iridescence displayed on polished surfaces, which is caused by optical interference in microscopic lamellae within the ternary feldspars. The larvikite complex consists of different intrusions, defining several ring- shaped structures, emplaced during a period of approximately five million years. Following this pattern, several commercial subtypes of larvikite, characterised by their colour and iridescence, have been mapped. Four of these subtypes are being exploited at the present time and define the most important reserves in the short run. Some other subtypes are less attractive in the present market situation, but may provide an interesting potential for the future. However, the industrial value of the larvikite also depends on other geological features, such as various types of dykes, faults and fractures, ductile deformation zones, late-stage magmatic and hydrothermal alteration and deep weathering. When combining the distribution pattern of such features with the map of the larvikite subtypes, it is possible to delineate various types of larvikite deposit that are considered to have commercial value in the short or long term. Finally, reserve estimates for the different types have been made, showing that some of the most attractive types have rather limited known reserves if the present level of production is maintained or increased. Heldal, T., Kjølle, I., Meyer, G.B. and Dahlgren, S. (008) National treasure of global significance. Dimension-stone deposits in larvikite, Oslo igneous province, Norway. In Slagstad, T. (ed.) Geology for Society, Geological Survey of Norway Special Publica- tion, 11, pp. –8. Tom Heldal, Idunn Kjølle, Gurli B. Meyer and Sven Dahlgren Introduction view, the larvikites are important for understanding the tectono- magmatic processes responsible for the formation of the Oslo The name ‘laurvikite’