DEFINING EXPLORATION TARGETS FROM REGIONAL SURVEYS - NORWAY. Tom Heldal, Geological Survey of Norway

Transcription

1 DEFINING EXPLORATION TARGETS FROM REGIONAL SURVEYS - NORWAY Tom Heldal, Geological Survey of Norway

2 Mineral resource Value chain at NGU Regional mapping: geology, geophysics, geochemistry Interpretation and geomodels Defining and safeguarding prospects and provinces

3 Government programs mineral resources MINN = Mineral resources In Northern Norway (25 mill. NOK pr year) MINS = MINeral resources in Southern Norway (?) 10 mill. NOK 2015 MINN2 = Mineral resources In Northern Norway 2, (?) 20 mill. NOK 2015

4 Activities Geophysical mapping (mag, rad, partly EM) Soil sample geochemistry Geological mapping Geological interpretation/exploration models 3D interpretation

5 Magnetic Radiometric Electromagnetic Maps and datasets Soil geochemistry Bedrock geology Mineral occurrences Maps for planning and safeguarding

6 Geophysical mapping status 2014 Geophysical mapping - plan ?? Covered area Covered area Plans 1. priority 2. priority

7 MINN soil geochemistry Example: Cu ca till samples

8 Bedrock 1: Coming soon!

9 Field geology Finnmark Repparfjord Alta-Kvænangen Kautokeino Senja-Mauken Altevann-Dividalen Ofoten-Sørreisa Vesterålen Hattfjelldal Hattfjelldal; geokjemi Nord-Trøndelag og Fosen; geokjemi Nord-Trøndelag og Fosen Trondheimsfeltet Sirdal-Knaben Evje-Froland Bamble Kongsberg-Modum

10 EXAMPLES

11 Iron Formations in the Caledonides Stratiform IF Dunderlandsdal(Rana)-type Structural and stratigraphic interpretation Fe deposits Dunderlandsdalen Storhaugen, Salangsverket (P.M. Ihlen)

12 aided by high-res geophysical dataset 10 km Evenes-Bogen registered iron deposits Narvik

13 Copper mineralisations in AKTW Sediment-hosted (Storviknes Fm) Quartz/carbonate veins (Kvenvik Fm) Stratabound in albite felsite (Kvenvik Fm) Cu - Alta-Kvænangen Alta 20 km Mapping, sampling and analysing, chemostratigraphic and zircon dating

14 Cu-Zn (-Pb) VMS deposits; Palaeozoic Sulitjelma In northern Norway are several provinces with high potential for volcanogenic massive sulphide deposits. Mofjellet Bleikvassli Hattfjelldal Rana-Hemnes Grong- Stekenjokk Hattfjelldal - Not well studied - Correlation Rana-Hemnes/Grong-Stekenjokk - High-grade sulphide boulders (Scandinavian Resources)

15 Hattfjelldal Follow-up geochemistry (1 sample/2-4 km 2 ) High-resolution helicopter-borne geophysics Bedrock mapping, sampling, analysing Zn ppm Mineral soil EM-data Apparent resistivity 6600 Hz Photo: Ola Eggen

16 Sirdal-Knaben (S Norway): New interpretation of Mo occurrences = new exploration models Foto: Axel Műller

17 Structural interpretation/mapping - Kautokeino Au-Cu Karasjok Bidjovagge (Henderson & Viola 2013) Kautokeino

18 Senja New graphite deposits? EM-data Apparent resistivity 6600 Hz Graphite deposits Trælen Skaland Skaland Graphite (LNS) - annual production tonn graphite

19 What about palaeoplacer? No systematic approach, allthough one has been thinking about doing more on that Radiometric maps are helping in identifying ancient deep weathering profiles

20 So; Too many mineral occurrences in Norway have been investigated by too few geologist, too long time ago New approaches vital

21 GOING DOWN 3D

22 High-res geophysics + drill-hole logging = testing underground interpretation Magnetic data Ørtfjell EM data Apparent resistivity 6600 hz

23 NW Sennalandet reflection seismic profile SE Holmvann Gr. SG HG 1,5 km long snowstreamer Collaboration between NGU and University in Bergen (J. Gellein)

24 Karasjok Greenstone Belt Magmatic Ni-Cu-PGE Airborne Gravity Gradient data + magnetic data Co-operation with Store Norske Gull Lakselv Gallujavri Gallujavri Karasjok (Skaar 2014)

25 Area: 30 km x 20 km Depth: 3-5 km 3D modelling (Skaar 2014) AGG & magnetic data Field observations and samples GeoModeller & IGMAS+ (J.A. Skaar 2014)

26 NARROWING DOWN TO TARGET AREAS

27 Knowledge on the map Mineral occurrence (point) Prospect (area) Deposit, measured (area) Province (area with possibilities of new discoveries)

28 Province Measured deposit Prospect Hypothetical situation

29 Provinces, prospects and deposits, Mo i Rana N Norway

30 Ore provinces and deposits, Sulitjelma N Norway

31 Conclusion Provide maps and several types of datasets for the industry = databases with increasing coverage New interpretation and geomodels = better exloration models Defining areas of interest (and NO interest) = safeguarding and societal accept

32 but There are many other issues to solve to get acceptance for mining Societal acceptance is a large issue, that must be faced from many angles

33 Thanks to Canada, the Nordic countries, Greenland, USA, Russia and Iceland for good progress in the CIRCUM-ARCTIC MINERAL RESOURCE PROJECT The Mineral Resource project began in 2012 using an existing Nordic-NW Russian oregeological database (FODD) as a model. All the geological surveys are participating Financial support is being provided by the Ministry of Foreign Affairs of Norway A draft base map has been prepared (by GSC) Maps, books and databases to be published at IGC Cape Town 2016

34 Thanks to all the teams at NGU

35 and to you for listening!