Metallic mineral deposits in the Nordic countries

Weihed, Pär; Eilu, Pasi; Larsen, Rune B.; Stendal, Henrik; Tontti, Mikko

doi:10.18814/epiiugs/2008/v31i1/017

Cited by 15 publications

(2 citation statements)

References 30 publications

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“…The northern Norrbotten area of Sweden is an economically important metallogenic province and mining district (Weihed et al, 2008). For example, about 90 % of European iron ore is annually produced in the area from two of the world's largest underground iron mines at Kiirunavaara and Malmberget (LKAB, 2017;OECD, 2017).…”

Section: Introductionmentioning

confidence: 99%

Evolution of structures and hydrothermal alteration in a Palaeoproterozoic supracrustal belt: Constraining paired deformation–fluid flow events in an Fe and Cu–Au prospective terrain in northern Sweden

Andersson

Lynch

2020

Solid Earth

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Abstract. An approximately 90 km long Palaeoproterozoic supracrustal belt in the northwestern Norrbotten ore province (northernmost Sweden) was investigated to characterize its structural components, assess hydrothermal alteration–structural geology correlations, and constrain a paired deformation–fluid flow evolution for the belt. New geological mapping of five key areas (Eustiljåkk, Ekströmsberg, Tjårrojåkka, Kaitum West, and Fjällåsen–Allavaara) indicates two major compressional events (D1 and D2) have affected the belt, with each associated with hydrothermal alteration types typical for iron oxide–apatite and iron oxide Cu–Au systems in the region. Early D1 generated a regionally distributed, penetrative S1 foliation and oblique reverse shear zones that show a southwest-block-up sense of shear that formed in response to NE–SW crustal shortening. Peak regional metamorphism at epidote–amphibolite facies broadly overlaps with this D1 event. Based on overprinting relationships, D1 is associated with regional scapolite ± albite, magnetite + amphibole, and late calcite alteration of mafic rock types. These hydrothermal mineral associations linked to D1 structures may form part of a regionally pervasive evolving fluid flow event but are separated in this study by crosscutting relationships. During D2 deformation, folding of S0–S1 structures generated F2 folds with steeply plunging fold axes in low-strain areas. NNW-trending D1 shear zones experienced reverse dip-slip reactivation and strike-slip-dominated movements along steep, E–W-trending D2 shear zones, producing brittle-plastic structures. Hydrothermal alteration linked to D2 structures is a predominantly potassic–ferroan association comprising K-feldspar ± epidote ± quartz ± biotite ± magnetite ± sericite ± sulfides. Locally, syn- or post-tectonic calcite is the main alteration mineral in D2 shear zones that intersect mafic rocks. Our results highlight the importance of combining structural geology with the study of hydrothermal alterations at regional to belt scales to understand the temporal–spatial relationship between mineralized systems. Based on the mapping results and microstructural investigations as well as a review of earlier tectonic models presented for adjacent areas, we suggest a new structural model for this part of the northern Fennoscandian Shield. The new model emphasizes the importance of reactivation of early structures, and the model harmonizes with tectonic models presented by earlier workers based mainly on petrology of the northern Norrbotten area.

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Section: Introductionmentioning

confidence: 99%

Evolution of structures and hydrothermal alteration in a Palaeoproterozoic supracrustal belt: Constraining paired deformation–fluid flow events in an Fe and Cu–Au prospective terrain in northern Sweden

Andersson

Lynch

2020

Solid Earth

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“…Rasvumchorr, Kukisvumchorr, Yuksporr, Koashva, Niorkpakhk, Oleny Ruchey, Partomchorr). L'apatite, principal minéral du minerai exploité contient 40-41 % poids P2O5, 1,8-3,5 % poids SrO, 9 000-11 000 ppm REE, et 500-900 ppm Y. Les ressources mesurées pour les gisements de l'intrusion de Khibiny sont estimées à près de 3 200 Mt @ 0,36 % REO et 14,87 % P2O5 (Eilu et al, 2013;Weihed et al, 2013 ;Kalashnikov et al, 2016). De nombreux minéraux de REE ont été identifiés : eudialyte, loparite, fluorapatite, ancylite-(Ce), bélovite-(Ce), etc.…”

Section: Péninsule De Kola-carélieunclassified