Structural evolution of two ore-bearing Palaeoproterozoic metasupracrustal belts in the Kiruna area, Northwestern Fennoscandian Shield
In this project, two key study areas in the northwestern Fennoscandian Shield are under investigation. The “Western supracrustal belt” and “Central Kiruna area” are both located along lithotectonically comparable Rhyacian-Orosirian metasupracrustal belts and both areas are characterized by iron oxid...
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Luleå tekniska universitet, Geovetenskap och miljöteknik
2019
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ftluleatu:oai:DiVA.org:ltu-72034 2023-05-15T16:12:56+02:00 Structural evolution of two ore-bearing Palaeoproterozoic metasupracrustal belts in the Kiruna area, Northwestern Fennoscandian Shield Andersson, Joel 2019 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-72034 eng eng Luleå tekniska universitet, Geovetenskap och miljöteknik Luleå Licentiate thesis / Luleå University of Technology, 1402-1757 http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-72034 urn:isbn:978-91-7790-287-4 urn:isbn:978-91-7790-288-1 info:eu-repo/semantics/openAccess Geology Geologi Licentiate thesis, comprehensive summary info:eu-repo/semantics/masterThesis text 2019 ftluleatu 2022-10-25T20:57:10Z In this project, two key study areas in the northwestern Fennoscandian Shield are under investigation. The “Western supracrustal belt” and “Central Kiruna area” are both located along lithotectonically comparable Rhyacian-Orosirian metasupracrustal belts and both areas are characterized by iron oxide-apatite (IOA) and iron oxide-copper-gold (IOCG)-style mineralizations and related hydrothermal alterations. The area is in general well studied but the structural evolution remains unresolved. In order to build a structural framework for the Kiruna area, the number of deformation events, kinematics, geometries, mineralogy and interrelationships of the dominant structures are under focus in this study. The paired structural-alteration configuration is targeted in order to constrain the relative timing of dominant structures and mineral alteration parageneses in order to use these systems as structural vectors of mineralized systems. Furthermore, the Orosirian stratigraphy is re-evaluated in order to constrain the pre-compressional geological history of the study areas. This is important as it controls the character of the structural development during subsequent compression forming the sub-surface architecture as we see today. The Orosirian stratigraphy suggests the development of a syn-extensional basin in Kiruna where iron oxide-apatite deposits were emplaced. This basin was subsequently inverted accompanied by shearing, folding, and faulting during D1 and D2, refolded during D3, and further fractured during D4. The shortening directions inferred during the deformation events suggest a clockwise rotation of the stress field from NE-SW (D1) to E-W (D2) and finally NNW-SSE (D3). Regional scapolite ± albite alteration is interpreted to be coeval with regional amphibole + magnetite alteration during D1. Mineral alteration parageneses linked to D2 is more potassic in character and often structurally controlled by shear zones. As a regional generalization, the potassic dominated D2-alteration is characterized by sericite ... Master Thesis Fennoscandian Kiruna Luleå University of Technology Publications (DiVA) Kiruna |
institution |
Open Polar |
collection |
Luleå University of Technology Publications (DiVA) |
op_collection_id |
ftluleatu |
language |
English |
topic |
Geology Geologi |
spellingShingle |
Geology Geologi Andersson, Joel Structural evolution of two ore-bearing Palaeoproterozoic metasupracrustal belts in the Kiruna area, Northwestern Fennoscandian Shield |
topic_facet |
Geology Geologi |
description |
In this project, two key study areas in the northwestern Fennoscandian Shield are under investigation. The “Western supracrustal belt” and “Central Kiruna area” are both located along lithotectonically comparable Rhyacian-Orosirian metasupracrustal belts and both areas are characterized by iron oxide-apatite (IOA) and iron oxide-copper-gold (IOCG)-style mineralizations and related hydrothermal alterations. The area is in general well studied but the structural evolution remains unresolved. In order to build a structural framework for the Kiruna area, the number of deformation events, kinematics, geometries, mineralogy and interrelationships of the dominant structures are under focus in this study. The paired structural-alteration configuration is targeted in order to constrain the relative timing of dominant structures and mineral alteration parageneses in order to use these systems as structural vectors of mineralized systems. Furthermore, the Orosirian stratigraphy is re-evaluated in order to constrain the pre-compressional geological history of the study areas. This is important as it controls the character of the structural development during subsequent compression forming the sub-surface architecture as we see today. The Orosirian stratigraphy suggests the development of a syn-extensional basin in Kiruna where iron oxide-apatite deposits were emplaced. This basin was subsequently inverted accompanied by shearing, folding, and faulting during D1 and D2, refolded during D3, and further fractured during D4. The shortening directions inferred during the deformation events suggest a clockwise rotation of the stress field from NE-SW (D1) to E-W (D2) and finally NNW-SSE (D3). Regional scapolite ± albite alteration is interpreted to be coeval with regional amphibole + magnetite alteration during D1. Mineral alteration parageneses linked to D2 is more potassic in character and often structurally controlled by shear zones. As a regional generalization, the potassic dominated D2-alteration is characterized by sericite ... |
format |
Master Thesis |
author |
Andersson, Joel |
author_facet |
Andersson, Joel |
author_sort |
Andersson, Joel |
title |
Structural evolution of two ore-bearing Palaeoproterozoic metasupracrustal belts in the Kiruna area, Northwestern Fennoscandian Shield |
title_short |
Structural evolution of two ore-bearing Palaeoproterozoic metasupracrustal belts in the Kiruna area, Northwestern Fennoscandian Shield |
title_full |
Structural evolution of two ore-bearing Palaeoproterozoic metasupracrustal belts in the Kiruna area, Northwestern Fennoscandian Shield |
title_fullStr |
Structural evolution of two ore-bearing Palaeoproterozoic metasupracrustal belts in the Kiruna area, Northwestern Fennoscandian Shield |
title_full_unstemmed |
Structural evolution of two ore-bearing Palaeoproterozoic metasupracrustal belts in the Kiruna area, Northwestern Fennoscandian Shield |
title_sort |
structural evolution of two ore-bearing palaeoproterozoic metasupracrustal belts in the kiruna area, northwestern fennoscandian shield |
publisher |
Luleå tekniska universitet, Geovetenskap och miljöteknik |
publishDate |
2019 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-72034 |
geographic |
Kiruna |
geographic_facet |
Kiruna |
genre |
Fennoscandian Kiruna |
genre_facet |
Fennoscandian Kiruna |
op_relation |
Licentiate thesis / Luleå University of Technology, 1402-1757 http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-72034 urn:isbn:978-91-7790-287-4 urn:isbn:978-91-7790-288-1 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1765998548281720832 |