University of Oulu

Moilanen, M., Hanski, E., Konnunaho, J. et al. Composition of iron oxides in Archean and Paleoproterozoic mafic-ultramafic hosted Ni-Cu-PGE deposits in northern Fennoscandia: application to mineral exploration. Miner Deposita (2020). https://doi.org/10.1007/s00126-020-00953-1

Composition of iron oxides in Archean and Paleoproterozoic mafic-ultramafic hosted Ni-Cu-PGE deposits in northern Fennoscandia : application to mineral exploration

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Author: Moilanen, M.1; Hanski, E.1; Konnunaho, J.2;
Organizations: 1Oulu Mining School, University of Oulu, P.O. Box 3000, FI-90014, Oulu, Finland
2Geological Survey of Finland, P.O. Box 77, FI-96101, Rovaniemi, Finland
3Geological Survey of Finland, P.O. Box 96, FI-02151, Espoo, Finland
4Mawson Oy, Ahjotie 7, 96320, Rovaniemi, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 7.8 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2020052839536
Language: English
Published: Springer Nature, 2020
Publish Date: 2020-05-28
Description:

Abstract

Using electron probe microanalyzer (EPMA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), we analyzed major and trace element compositions of iron oxides from Ni-Cu-PGE sulfide deposits hosted by mafic-ultramafic rocks in northern Fennoscandia, mostly focusing on Finland. The main research targets were the Archean Ruossakero Ni-(Cu) deposit; Tulppio dunite and related Ni-PGE mineralization; Hietaharju, Vaara, and Tainiovaara Ni-(Cu-PGE) deposits; and Paleoproterozoic Lomalampi PGE-(Ni-Cu) deposit. In addition, some reference samples from the Pechenga (Russia), Jinchuan (China), and Kevitsa (Finland) Ni-Cu-PGE sulfide deposits, and a barren komatiite sequence in the Kovero area (Finland) were studied. Magnetite and Cr-magnetite show a wide range of trace element compositions as a result of the variation of silicate and sulfide melt compositions and their post-magmatic modification history. Most importantly, the Ni content in oxide shows a positive correlation with the Ni tenor of the sulfide phase in equilibrium with magnetite, regardless of whether the sulfide assemblage is magmatic or post-magmatic in origin. The massive sulfide samples contain an oxide phase varying in composition from Cr-magnetite to magnetite, indicating that Cr-magnetite can crystallize directly from sulfide liquid. The Mg concentration of magnetites in massive sulfide samples is lowest among the samples analyzed, and this can be regarded as a diagnostic feature of an oxide phase crystallized together with primitive Fe-rich MSS (monosulfide solid solution). Our results show that magnetite geochemistry, plotted in appropriate discrimination diagrams, together with petrographical observations could be used as an indicator of potential Ni-(Cu-PGE) mineralization.

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Series: Mineralium deposita
ISSN: 0026-4598
ISSN-E: 1432-1866
ISSN-L: 0026-4598
Volume: In press
DOI: 10.1007/s00126-020-00953-1
OADOI: https://oadoi.org/10.1007/s00126-020-00953-1
Type of Publication: A1 Journal article – refereed
Field of Science: 1171 Geosciences
Subjects:
Funding: Open access funding provided by University of Oulu including Oulu University Hospital. This research was supported by the Academy of Finland (grant #281859), K.H. Renlund Foundation and Tauno Tönning Foundation.
Academy of Finland Grant Number: 281859
Detailed Information: 281859 (Academy of Finland Funding decision)
Dataset Reference: Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00126-020-00953-1) contains supplementary material, which is available to authorized users.
  https://doi.org/10.1007/s00126-020-00953-1
Copyright information: © The Author(s) 2020. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
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