Planned maintenance
A system upgrade is planned for 10/12-2024, at 12:00-13:00. During this time DiVA will be unavailable.
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Petrological and structural character of c. 1.88 Ga meta-volcanosedimentary rocks hosting iron oxide-copper-gold and related mineralisation in the Nautanen–Aitik area, northern Sweden
Sveriges geologiska undersökning.
Luleå University of Technology.
Sveriges geologiska undersökning.
Luleå University of Technology.
Show others and affiliations
2018 (English)In: SGU Rapporter och meddelanden, ISSN 0349-2176, Vol. 141, p. 107-150Article in journal (Refereed) Published
Abstract [en]

The petrological and deformation characteristics of a Palaeoproterozoic meta-volcanosedimentary sequence in the Nautanen–Aitik area (near Gällivare, northern Sweden) are presented. The investigated sequence (part of the Muorjevaara group) predominantly comprises metavolcaniclastic rocks displaying variable grain size, textural and syn-depositional features (e.g. grading, cross-laminae, compositional banding). Locally, poorly sorted agglomerate-like horizons with coarser clasts (lapilli-to block-size) occur. Interbedded sections of mainly fine-grained, volcanogenic (epiclastic) metasedimentary rocks contain syn-depositional features that suggest a sub-aqueous, relatively shallow depositional environment. Locally preserved cross-laminae in this unit provide evidence of way-up and paleocurrent directions. Intercalations of pelite, mica schist and amphibolitic schist also occur throughout the sequence. In general, least altered samples indicate a predominantly intermediate (basaltic andesitic to andesitic), calc-alkaline composition for the sequence.

U-Pb SIMS zircon dating of a meta-andesite horizon, intercalated within the sequence, has yielded a precise U-Pb concordia age of 1 878 ± 7 Ma (2σ, n = 12). This date constrains the timing of intermediate volcanism and the deposition of syn-volcanic epiclastic material. By inference, it also provides an estimate for the age of Muorjevaara group rocks hosting the Nautanen Cu-Au and Aitik Cu-Au-Ag deposits. When combined with lithogeochemical signatures, the new age also confirms a genetic link between the metavolcaniclastic package and gabbroic to dioritic intrusions in the area (e.g. the c. 1.88 Ga Aitik stock). Additionally, several zircon cores record 207Pb/206Pb apparent ages between c. 1.90 and 1.89 Ga, suggesting inheritance of marginally older volcanic ± plutonic material not exposed at the present erosion level.

The Nautanen–Aitik area contains the roughly north-northwest-trending Nautanen deformation zone (NDZ), a major composite brittle-ductile structure hosting hydrothermal iron oxide-Cu-Au (IOCG)-style mineralisation (e.g. the Nautanen deposit). Here, the bedrock is relatively intensely altered and sheared, and has been transposed into a sub-parallel high-strain zone predominantly consisting of a composite planar penetrative fabric. Outside the high-strain zone, relatively large-scale approximately north-northwest-aligned folds and discordant brittle structures occur. Magnetic susceptibility and VLF-resistivity modelling of the NDZ confirm that composite planar structures mainly dip steeply to the west-southwest and continue at depth.

Place, publisher, year, edition, pages
Uppsala: Sveriges geologiska undersökning , 2018. Vol. 141, p. 107-150
National Category
Geology
Research subject
The changing Earth
Identifiers
URN: urn:nbn:se:nrm:diva-3168OAI: oai:DiVA.org:nrm-3168DiVA, id: diva2:1272244
Available from: 2018-12-18 Created: 2018-12-18 Last updated: 2018-12-18Bibliographically approved

Open Access in DiVA

fulltext(109023 kB)252 downloads
File information
File name FULLTEXT01.pdfFile size 109023 kBChecksum SHA-512
e25c137f4837b1315734cca7eeb5524439a627de355b2b57204b0f3853603755eb62cf0153dc2266ee58e4a8c214abfa4a3677ac62a4fe01a9245ea920bb588f
Type fulltextMimetype application/pdf

Other links

http://resource.sgu.se/produkter/rm/rm141-rapport.pdf

Search in DiVA

By author/editor
Persson, Per-Olof
By organisation
Department of Geology
Geology

Search outside of DiVA

GoogleGoogle Scholar
Total: 252 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 277 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf