Data mining of petrophysical and lithogeochemical borehole data to elucidate the origin of seismic reflectivity within the Kevitsa Ni-Cu-PGE -bearing intrusion, northern Finland

Niina Marjut Junno, Emilia Anna-Liisa Koivisto, Ilmo Tapio Kukkonen, Alireza Malehmir, Chris Wijns, Markku Montonen

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The Kevitsa mafic-ultramafic intrusion, located within the Central Lapland Greenstone Belt in northern Finland, hosts a large, disseminated Ni-Cu-PGE sulphide deposit. A three-dimensional seismic reflection survey was conducted over the Kevitsa intrusion in 2010 primarily for open-pit mine planning and for deep mineral exploration purposes. In the Kevitsa three-dimensional seismic data, laterally continuous reflections are observed within a constrained region within the intrusion. In earlier studies, it has been suggested that this internal reflectivity mainly originates from contacts between the tops and more sulphide-rich bottoms of smaller scale, internally differentiated magma layers that represent a spectrum of olivine pyroxenites. However, this interpretation is not unequivocally supported by the borehole data. In this study, data mining, namely the Self-Organizing Map analysis, of extensive Kevitsa borehole data is used to investigate the possible causes for the observed internal reflectivity within the Kevitsa intrusion. Modelling of the effect of mineralization and alteration on the reflectivity properties of Kevitsa rock types, based on average modal compositions of the rock types, is presented to support the results of the Self-Organizing Map analysis. Based on the results, we suggest that the seismic reflectivity observed within the Kevitsa intrusion can possibly be attributed to alteration, and may also be linked to the presence of sulphide minerals.

Original languageEnglish
JournalGeophysical Prospecting
Volume68
Issue number1
Pages (from-to)82-102
Number of pages21
ISSN0016-8025
DOIs
Publication statusPublished - 1 Jan 2020
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 114 Physical sciences
  • 1171 Geosciences
  • Borehole geophysics
  • Petrophysics
  • Seismics
  • Interpretation
  • MASSIVE SULFIDE DEPOSITS
  • SELF-ORGANIZING MAPS
  • WHOLE-ROCK
  • EXPLORATION
  • MINE

Cite this

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title = "Data mining of petrophysical and lithogeochemical borehole data to elucidate the origin of seismic reflectivity within the Kevitsa Ni-Cu-PGE -bearing intrusion, northern Finland",
abstract = "The Kevitsa mafic-ultramafic intrusion, located within the Central Lapland Greenstone Belt in northern Finland, hosts a large, disseminated Ni-Cu-PGE sulphide deposit. A three-dimensional seismic reflection survey was conducted over the Kevitsa intrusion in 2010 primarily for open-pit mine planning and for deep mineral exploration purposes. In the Kevitsa three-dimensional seismic data, laterally continuous reflections are observed within a constrained region within the intrusion. In earlier studies, it has been suggested that this internal reflectivity mainly originates from contacts between the tops and more sulphide-rich bottoms of smaller scale, internally differentiated magma layers that represent a spectrum of olivine pyroxenites. However, this interpretation is not unequivocally supported by the borehole data. In this study, data mining, namely the Self-Organizing Map analysis, of extensive Kevitsa borehole data is used to investigate the possible causes for the observed internal reflectivity within the Kevitsa intrusion. Modelling of the effect of mineralization and alteration on the reflectivity properties of Kevitsa rock types, based on average modal compositions of the rock types, is presented to support the results of the Self-Organizing Map analysis. Based on the results, we suggest that the seismic reflectivity observed within the Kevitsa intrusion can possibly be attributed to alteration, and may also be linked to the presence of sulphide minerals.",
keywords = "114 Physical sciences, 1171 Geosciences, Borehole geophysics, Petrophysics, Seismics, Interpretation, MASSIVE SULFIDE DEPOSITS, SELF-ORGANIZING MAPS, WHOLE-ROCK, EXPLORATION, MINE",
author = "Junno, {Niina Marjut} and Koivisto, {Emilia Anna-Liisa} and Kukkonen, {Ilmo Tapio} and Alireza Malehmir and Chris Wijns and Markku Montonen",
year = "2020",
month = "1",
day = "1",
doi = "https://doi.org/10.1111/1365-2478.12907",
language = "English",
volume = "68",
pages = "82--102",
journal = "Geophysical Prospecting",
issn = "0016-8025",
publisher = "Wiley Blackwell",
number = "1",

}

Data mining of petrophysical and lithogeochemical borehole data to elucidate the origin of seismic reflectivity within the Kevitsa Ni-Cu-PGE -bearing intrusion, northern Finland. / Junno, Niina Marjut; Koivisto, Emilia Anna-Liisa; Kukkonen, Ilmo Tapio; Malehmir, Alireza; Wijns, Chris; Montonen, Markku.

In: Geophysical Prospecting, Vol. 68, No. 1, 01.01.2020, p. 82-102.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Data mining of petrophysical and lithogeochemical borehole data to elucidate the origin of seismic reflectivity within the Kevitsa Ni-Cu-PGE -bearing intrusion, northern Finland

AU - Junno, Niina Marjut

AU - Koivisto, Emilia Anna-Liisa

AU - Kukkonen, Ilmo Tapio

AU - Malehmir, Alireza

AU - Wijns, Chris

AU - Montonen, Markku

PY - 2020/1/1

Y1 - 2020/1/1

N2 - The Kevitsa mafic-ultramafic intrusion, located within the Central Lapland Greenstone Belt in northern Finland, hosts a large, disseminated Ni-Cu-PGE sulphide deposit. A three-dimensional seismic reflection survey was conducted over the Kevitsa intrusion in 2010 primarily for open-pit mine planning and for deep mineral exploration purposes. In the Kevitsa three-dimensional seismic data, laterally continuous reflections are observed within a constrained region within the intrusion. In earlier studies, it has been suggested that this internal reflectivity mainly originates from contacts between the tops and more sulphide-rich bottoms of smaller scale, internally differentiated magma layers that represent a spectrum of olivine pyroxenites. However, this interpretation is not unequivocally supported by the borehole data. In this study, data mining, namely the Self-Organizing Map analysis, of extensive Kevitsa borehole data is used to investigate the possible causes for the observed internal reflectivity within the Kevitsa intrusion. Modelling of the effect of mineralization and alteration on the reflectivity properties of Kevitsa rock types, based on average modal compositions of the rock types, is presented to support the results of the Self-Organizing Map analysis. Based on the results, we suggest that the seismic reflectivity observed within the Kevitsa intrusion can possibly be attributed to alteration, and may also be linked to the presence of sulphide minerals.

AB - The Kevitsa mafic-ultramafic intrusion, located within the Central Lapland Greenstone Belt in northern Finland, hosts a large, disseminated Ni-Cu-PGE sulphide deposit. A three-dimensional seismic reflection survey was conducted over the Kevitsa intrusion in 2010 primarily for open-pit mine planning and for deep mineral exploration purposes. In the Kevitsa three-dimensional seismic data, laterally continuous reflections are observed within a constrained region within the intrusion. In earlier studies, it has been suggested that this internal reflectivity mainly originates from contacts between the tops and more sulphide-rich bottoms of smaller scale, internally differentiated magma layers that represent a spectrum of olivine pyroxenites. However, this interpretation is not unequivocally supported by the borehole data. In this study, data mining, namely the Self-Organizing Map analysis, of extensive Kevitsa borehole data is used to investigate the possible causes for the observed internal reflectivity within the Kevitsa intrusion. Modelling of the effect of mineralization and alteration on the reflectivity properties of Kevitsa rock types, based on average modal compositions of the rock types, is presented to support the results of the Self-Organizing Map analysis. Based on the results, we suggest that the seismic reflectivity observed within the Kevitsa intrusion can possibly be attributed to alteration, and may also be linked to the presence of sulphide minerals.

KW - 114 Physical sciences

KW - 1171 Geosciences

KW - Borehole geophysics

KW - Petrophysics

KW - Seismics

KW - Interpretation

KW - MASSIVE SULFIDE DEPOSITS

KW - SELF-ORGANIZING MAPS

KW - WHOLE-ROCK

KW - EXPLORATION

KW - MINE

U2 - https://doi.org/10.1111/1365-2478.12907

DO - https://doi.org/10.1111/1365-2478.12907

M3 - Article

VL - 68

SP - 82

EP - 102

JO - Geophysical Prospecting

JF - Geophysical Prospecting

SN - 0016-8025

IS - 1

ER -