Developments of the Mineral Systems and Mineral Prospectivity Mapping (MinSysPro) project in
Finnish Lapland
Ferenc Molnár
Geological Survey of Finland
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Subjects of Presentation
• Background of the project: aims and objectives
• The mineral system approach and mineral prospectivity mapping
• The MINSYSPRO consortium: research teams, international cooperation, research methods
• Orogenic gold mineral systems in Finnish Lapland - targets - current results
Native gold
Rompas
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Aims and Objectives of the MinSysPro Project
Development of a knowledge-based and cost effective exploration method which is capable of predicting mineral resources under cover.
Systematic collection of new knowledge of processes leading to formation of orogenic gold and magmatic sulphide/oxide mineral systems in Finnish Lapland by application of modern, cutting edge research methods. Development methods of computer-based conceptual and empirical mineral prospectivity mapping by using the new results of research on mineral systems in Lapland.
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Mineral Systems and Models for Mineral Prospectivity Mapping
Mineral Systems - all geological factors that control origin and preservation of mineral deposits Mineral System Model - definition of sources transportation accumulation re-mobilisation mappable parameters Target generation -incorporation of mappable parameters of mineral system models into mineral prospectivity evaluations
approach
modeling
prospecting
ore components
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Vectors to ore
Conditions of primary and secondary enrichment
or dispersion of metals
Mineral Systems: Critical Processes and Parameters
Parameters
Structural control
Geodynamic setting
Relative and absolute timing of processes
Processes
Applicable to magmatic and hydrothermalmineral systems
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Selection of the relevant data
based on the exploration model
or mineral system model
Spatial analysis
Validation, targeting
Mineral Prospectivity Mapping
Input pattern generation
V. Nykänen
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Orogenic Gold Mineral systems
Ferenc Molnár Hugh O`Brien Peter Sorjonen-Ward Sayeb Muhammad Postdoctoral researchers: Alexander Middleton from 01.01.2015 to 05.02.2016
Matti Kurhila from 01.05.2016 to 30.01.2017
Antonin Richard Univ. Lorraine
Iain Pitcairn Univ. Stockholm
Harry Oduro Gareth Izon Univ. St. Andrews
Holly Stein Univ. Oslo Univ. Colorado
Jussi-Petteri Suuronen The European Synchro- tron Radiation Facility
Mineral Prospectivity Mapping
Vesa Nykänen Satu Mertanen Tero Niiranen Eeva-Lisa Laine Ilkka Lahti Jouni Lerssi Postdoctoral researcher: T.B.N. from 01.08.2016 to 30.08.2018
Magmatic Mineral Systems
Eero Hanski Shenghong Yang Markku Pirttijärvi Hannu Huhma Tuomo Karinen Tuomo Törmänen Yann Lahaye PhD students: Jukka Konnunaho Marko Moilanen Kirsi Luolavirta Fangfang Guo
Wolfgang Maier Univ. Cardiff
Richard Walker Igor Puchtel Univ. Maryland
Wenjun Qu Xiaoping Xia Chinese Acad. Sci.
Sergei Svetov Artem Mokrushin Paul Priprachkin Russian Acad. Sci.
Industry partners Agnico-Eagle Finland Oy. Dragon Mining Oy. Mawson Reosurces Oy. First Quantum Oy. Anglo-American Plc.
Research Consortium
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Nu AttoM HR-ICP-MS with laser microprobe
Nu Plasma MC-ICP-MS with laser microprobe
JEOL JSM 7100F high resolution
FE-SEM
Mineralogy Geochronology, stable and radiogenic isotopes, trace elements
Linkam MDSG 600 microT
Fluid inclusions
Cutting Edge Analytical Methods Applied to the Mineral System Research
• In situ analyses of individual minerals with high spatial resolution (micrometer scale)
• Multiple stable and radiogenic isotope, trace element and fluid inclusion analyses from the same sample and even from the same mineral grain.
• Research on the applicability of unconvetional stable and radiogenic isotope systems in better understandig ore- forming processes.
H. O`Brien, Y. Lahaye
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Tragets of Research: Orogenic Gold Mineral Systems in Lapland
Examples presented: Multiple hydrothermal processes – geochronology Sources of fluids, vectoring – isotopes, trace elements in minerals Structural control on mineralisation – MicroCT
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Granite 1.84-1.80 Ga
Garnet Sm-Nd cooling age
1.75 Ga
Mafic volcanic (amphibolite) unit surrounded by calc-silicate and mica schist units Lower amphibolite facies Svecofennian metamorphism F1 folding: E-W compression; F2 folding: N-S compression Occurrence of black shales in the vicinity of the mineralization
Unusually high concentrations of gold are strictly associated with uraninite and pyrobitumen.
Regional and local geology:
Rompas Au-U mineralization Rompas
Rajapalot Palokas
Undeformed granite intrusions
Migmatite leucosomes
1.78 Ga
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Pyrobitumen with uraninite grains
Uraninite with galena and gold
Calcite
Gold
The Uraninite-Gold and Gold-Pyrobitumen Association in the Rompas Property
Pyrobitumen Uraninite
Galena
Altaite
Gold + hunchunite
Gold
Gold-hunchunite-galena-altaite in fractures of uraninite and pyrobytumen
Gold in pyrobitumen and in the shrinkage cracks of pyrobitumen
Gold
Gold
Precipitation of gold post-dates accumulation of pyrobitumen.
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
0.0
0.2
0.4
0.6
0 2 4 6 8 10 12
207Pb/235U
20
6P
b/2
38U
600
1000
1400
1800
2200
2600
data-point error ellipses are 2s
Lower intercept at 416±85
Upper intercept at 1993±20 [±21] MaMSWD = 0.86; probability of fit = 0.55
U-Pb Ages for Uraninite, Rompas
core
rim
Single grain core
rim
1993 ± 20 Ma
0.0
0.2
0.4
0.6
0 2 4 6 8 10 12
207Pb/235U
20
6P
b/2
38U
600
1000
1400
1800
2200
2600
Lower intercept at 90±270 &MaUpper intercept at 1813±23 [±24] MaMSWD = 1.04; Probability of fit = 0.41
data-point error ellipses are 2s
Grains with Low U/Th ratio 1813 ± 23 Ma
0.0
0.2
0.4
0.6
0 2 4 6 8 10 12
207Pb/235U
20
6P
b/2
38U
600
1000
1400
1800
2200
2600
Intercepts at
521±390 & 2095±110 MaMSWD = 2.2; Probability of fit = 0.008
data-point error ellipses are 2s
Grains with High U/Th ratio 2095 ± 110 Ma
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Re, ppm 187Os, ppb Age, Ma
303 (2) 5722 (5) 1778 ± 13
320.8 (4) 6077 (5) 1782 ± 6
1.581 (5) 33.80 (3) 2007 ± 9
70.7 (1) 1538 (1) 2043 ± 8
109.6 (2) 2362 (2) 2023 ± 7
376.8 (5) 8548 (7) 2128 ± 8
135.1 (2) 3124 (2) 2168 ± 8
uraninite
molybdenite
molybdenite grains drilled out
Four Rompas Molybdenites
Palokas
Molybdenite Re-Os Ages at Rompas and Palokas
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
The Au-U Mineralisation at Rompas is a
Result of a ≈350 Ma Long Geological Evolution
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Preparation of traps for precipitation of
gold
Xenotime
Monazite
Xenotime
Xenotime
aspy
nat. Bi
nat. Au
po
Repeated Hydrothermal Events Along the Same Regional Structure: U-Pb Dating of Hydrothermal Xenotime and Monazite,
Iso-Kuotko, Central Lapland Greenstone Belt
Iso-Kuotko Au-deposit
In situ LA ICPMS analyses with high spatial resolution
Xenotime
Stage 1: 1854-1862 Ma Stage 2: 1757-1768 Ma
Laser-ablation spots of analyses
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Sources of Fluids: Sulphur-Isotope Data Central Lapland Greenstone Belt
Hanski, 2005
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
Development Tools For Vectoring Towards Ore: Trace Elements and Sulphur Isotopes in Pyrite and Other Sulphides
Example: Suurikuusikko gold deposit
Zoning in pyrite: in situ LA ICPMS analyses of trace elements and sulphur isotopes
Sulphur isotope data and Au-contents in pyrite analysed from the same spots
3D distribution of auriferrous arsenopyrite
and pyrite in the host rock.
X-ray computed microtomography.
3D distribution of gold grains and mineral inclusions in arsenopyrite.
Synchrotron radiation based nanotomography.
3D Micro- and Nanoscale Analysis of the Structural Control on Distribution of Ore Minerals
Suurikuusikko gold deposit
M. Sayab
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project
MinSysPro Project - Summary
• Systematic and multidiciplinary research based on the holistic mineral system approach.
• Filling up gaps of knowledge of geological processes which led to the economically importand precious-, base- and critical metal mineral resources in Finnish Lapland.
• Development of new mineral system models and mineral prospectivity mapping methods for better evaluation of targets for mineral exploration
Minerals – Source for growth , 03.06.2016 MINSYSPRO Project