Sven Dahlgren

• Polák, Ladislav; Ackerman, Lukáš; Magna, Tomáš; Rapprich, Vladislav; Bizimis, Michael & Giebel, Robert Johannes [Vis alle 9 forfattere av denne artikkelen] (2026). Neodymium isotope constraints from global carbonatites on the possible presence of a long-lived enriched mantle reservoir. Lithos. ISSN 0024-4937. 538-539. doi: 10.1016/j.lithos.2026.108599. Fulltekst i vitenarkiv
• Polák, Ladislav; Ackerman, Lukáš; Magna, Tomáš; Rapprich, Vladislav; Bizimis, Michael & Giebel, R. Johannes [Vis alle 8 forfattere av denne artikkelen] (2024). Significance of highly siderophile element and Re–Os isotope systematics in global carbonatites. Chemie der Erde. ISSN 0009-2819. 84(4). doi: 10.1016/j.chemer.2024.126095. Fulltekst i vitenarkiv
• Haanes, Hallvard; Dahlgren, Sven Harald & Rudjord, Anne Liv (2023). Cold season dose rate contributions from gamma, radon, thoron or progeny in legacy mines with high natural background radiation. Radiation Protection Dosimetry. ISSN 0144-8420. 199(12), s. 1284–1294. doi: 10.1093/rpd/ncad178. Fulltekst i vitenarkiv Vis sammendrag

  Abstract In areas with high natural background radiation, underground cavities tend to have high levels of airborne radionuclides. Within mines, occupancy may involve significant exposure to airborne radionuclides like radon (222Rn), thoron (220Rn) and progeny. The Fen carbonatite complex in Norway has legacy mines going through bedrock with significantly elevated levels of uranium (238U) and especially thorium (232Th), and significant levels of their progeny 222Rn and 220Rn. There are also significantly elevated levels of gamma radiation in these mines. These mines are naturally chimney ventilated and release large volumes of air to the outdoors giving a large local outdoor impact. We placed alpha track detectors at several localities within these mines to measure airborne radionuclides and measured gamma radiation of bedrock at each locality. The bedrock within the mines shows levels up to 1900 Bq kg−1 for 238U, 12 000 Bq kg−1 for 232Th and gamma dose rates up to 11 μSv h−1. Maximum levels of airborne radionuclides were 45 000 Bq m−3 for 220Rn and 6900 Bq m−3 for 222Rn. In addition, we measured levels of thoron progeny (TnP). In order to estimate radiation dose contribution, TnP should be assessed rather than 220Rn, but deposition-based detectors may be biased by the airflow of mine-draft. We present dose rate contributions using UNSCEAR dose conversion factors, and correcting for airflow bias, finding a combined cold season dose rate within these mines of 17–24 μSv h−1. Interestingly, fractional dose rate contributions vary from 0.02 to 0.6 for gamma, 0.33 to 0.95 for radon and 0.1 to 0.25 for TnP.

• Dietzel, Christian AF; Kristandt, Tim; Dahlgren, Sven Harald; Giebel, R Johannes; Marks, Michael A. W. & Wenzel, Thomas [Vis alle 7 forfattere av denne artikkelen] (2019). Hydrothermal processes in the Fen alkaline-carbonatite complex, southern Norway. Ore Geology Reviews. ISSN 0169-1368. 111, s. 1–18. doi: 10.1016/j.oregeorev.2019.102969. Fulltekst i vitenarkiv
• Elliott, H.A.L.; Wall, F.; Chakhmouradian, A.R.; Siegfried, P.R.; Dahlgren, Sven Harald & Weatherley, S. [Vis alle 10 forfattere av denne artikkelen] (2018). Fenites associated with carbonatite complexes: A review. Ore Geology Reviews. ISSN 0169-1368. 93, s. 38–59. doi: 10.1016/j.oregeorev.2017.12.003. Fulltekst i vitenarkiv
• Haanes, Hallvard; Finne, Ingvild E.; Kolstad, Trine; Mauring, Alexander; Dahlgren, Sven Harald & Rudjord, Anne Liv (2016). Outdoor thoron and progeny in a thorium rich area with old decommissioned mines and waste rock. Journal of Environmental Radioactivity. ISSN 0265-931X. 162-163, s. 23–32. doi: 10.1016/j.jenvrad.2016.05.005. Fulltekst i vitenarkiv

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• Tonti-Filippini, Justin Antony Dean; Antonio, Paul Yves Jean; Dahlgren, Sven Harald; Boer, R. de; Gallo, Leandro C. & Silkoset, Petter [Vis alle 9 forfattere av denne artikkelen] (2026). Ediacara obscura: Unveiling hidden magnetisations in the Fen complex, southern Norway. Fulltekst i vitenarkiv
• Tonti-Filippini, Justin Antony Dean; Antonio, Paul Yves Jean; Dahlgren, Sven Harald; Boer, R. de; Gallo, Leandro C. & Silkoset, Petter [Vis alle 9 forfattere av denne artikkelen] (2026). Ediacara obscura: Unveiling hidden magnetisations in the Fen complex, southern Norway. Fulltekst i vitenarkiv
• Olaussen, Snorre; Dahlgren, Sven Harald; Falcon-Lang, Howard J.; Larsen, Bjørn Tore; Müller, Reidar & Nakrem, Hans Arne (2024). Pennsylvanian facies and sequence stratigraphic analysis in the Oslo Graben: distinguishing tectonic and eustatic forcing during initial rifting. Fulltekst i vitenarkiv Vis sammendrag

  The Pennsylvanian Asker Group of Norway, up to 90 m thick, comprises the basal sedimentary-fill of the Carboniferous -Permian Oslo Rift, a volcanically active basin. Three stratigraphic units are recognized, from base to top, as the Kolsås, Tanum and Skaugum formations. Minor extensional tectonism occurred during deposition of the Asker Group. However, during the Late Paleozoic icehouse, high amplitude eustasy was another factor influencing base-level, and in this presentation, we present evidence to distinguish fault-controlled depositional systems influenced by tectonism and eustatic controls. The Kolsås Formation comprises red beds deposited within alluvial plain environments developed during an interval of passive subsidence. In contrast the overlying Tanum Formation shows a transgressive-regressive pattern, commencing with terrestrial facies comprising the deposits of ephemeral streams and flood plains with thick calcretes, and passing upward into shoreface/delta front facies capped by ?Moscovian shallow marine limestone, before being partly eroded by braid plain deposits, marking renewed base-level fall. The regional fluvial paleoflow direction in the Tanum Formation is towards the master faults. Drainage pattern, growth faulting and the widespread coarsening upward trend of the Kolsås and Tanum formations all suggest an upward increasing tectonic activity in a dip slope setting within the initial rift phase. A Kasimovian-Gzhelian (?Stephanian B/C) plant-fossil rich succession of wetland, lacustrine and bay mouth bar facies is sandwiched between braid plain facies of the Tanum Formation and an overlying volcanoclastic fanglomerate of the Skaugum Formation is indicative of a sudden sea level rise. The abrupt changes in facies and numerous hiatuses or lacunas seen in the Pennsylvanian Asker Group are probably linked to Pennsylvanian glacio-eustasy, and the enigmatic late Moscovian marine incursion in the Tanum Formation might be correlative with the amplified eustatic signal close to the Moscovian-Kasimovian boundary in the US midcontinental and Donets Basin coastal onlap datasets.

• Kullerud, Lars & Dahlgren, Sven Harald (1992). Små korn - lang historie. Endelig zirkondatering i Norge. Geonytt. ISSN 0802-6173. Fulltekst i vitenarkiv
• Kullerud, Lars & Dahlgren, Sven Harald (1990). iming of the high grade metamorphism in the Bamble sector, South Norway. Geonytt. ISSN 0802-6173. Fulltekst i vitenarkiv

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