Unraveling the Tectonic History of the Aurek Metagabbro within the Seve Nappe Complex, Scandinavian Caledonides
The Scandinavian Caledonides form a mountain range comprising nappe stacks of numerous far-travelled thrust sheets. The thrust sheets consist of diverse lithologies representing pre- and synorogenic sedimentary and igneous rocks subsequently metamorphosed to various degrees, from the Late Neoprotero...
Main Author: | |
---|---|
Format: | Bachelor Thesis |
Language: | English |
Published: |
Uppsala universitet, Institutionen för geovetenskaper
2021
|
Subjects: | |
Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-455444 |
id |
ftuppsalauniv:oai:DiVA.org:uu-455444 |
---|---|
record_format |
openpolar |
spelling |
ftuppsalauniv:oai:DiVA.org:uu-455444 2023-05-15T17:44:35+02:00 Unraveling the Tectonic History of the Aurek Metagabbro within the Seve Nappe Complex, Scandinavian Caledonides Undersökningsstudie av metagabbro i Aurek och dess tektoniska utveckling inom Seveskollan, Skandinaviska Kaledoniderna Rousku, Sabine 2021 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-455444 eng eng Uppsala universitet, Institutionen för geovetenskaper Examensarbete vid Institutionen för geovetenskaper, 1650-6553 523 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-455444 info:eu-repo/semantics/openAccess Scandinavian Caledonides Seve Nappe Complex Aurek metagabbro Kebnekaise Mountains Zircon U-Pb Geochronology Thermodynamic modeling Geochemistry Skandinaviska Kaledoniderna Seveskollan Kebnekaisebergen zirkon U-Pb geokronologi Termodynamisk modellering Geokemi Geology Geologi Student thesis info:eu-repo/semantics/bachelorThesis text 2021 ftuppsalauniv 2023-02-23T21:59:15Z The Scandinavian Caledonides form a mountain range comprising nappe stacks of numerous far-travelled thrust sheets. The thrust sheets consist of diverse lithologies representing pre- and synorogenic sedimentary and igneous rocks subsequently metamorphosed to various degrees, from the Late Neoproterozoic to Middle Devonian. In particular, (ultra)-high-grade metamorphic rocks have been recorded in the Seve Nappe Complex (SNC), extending >1000 km along strike of the Scandinavian Caledonides. Included in the SNC of northern Sweden is the Vássačorru Igneous Complex (VIC), consisting of bimodal magmatic suites, that formed c. 845 Ma. Fieldwork was conducted in the Kebnekaise mountains of northern Sweden, focusing on the high-grade Aurek metagabbro within the VIC of the SNC. Aurek is a key locality representing both initial stages of Iapetus Ocean formation in the Ediacaran and later stage Caledonian subduction affinities, from the collision between Laurentia and Baltica. In this study, petrological description, zircon U-Pb geochronology, mineral chemistry analysis, whole rock composition, and thermodynamic modeling was performed. Zircon U-Pb geochronology yielded protolith ages of 609±2.5 Ma, and 614±2.3 Ma, suggesting the Aurek metagabbro to not be part of the VIC, as has previously been described. The age of Aurek can instead be correlated to the Kebnekaise Dyke Swarms at c. 607 Ma, in the Kebnekaise mountains. Whole rock major and trace element data of e.g., Al2O3 (15.0 – 25.0 ppm) versus SiO2 (46.0 – 53.0 ppm), Rb (2.0 – 18.0 ppm), Zr (8.0 – 58.0 ppm) versus Y (2.7 – 18.0 ppm), Th/Yb ratio 0.25 – 2.0 and Nb/Yb ratio 1.30 – 5.14, indicate assimilation of continental crust. These major and trace element signatures show that the protolith of the Aurek metagabbro probably was emplaced in a continental rift setting in the Ediacaran. Semi-quantitative thermodynamic modeling from this study present blueschist to amphibolite facies conditions for the Aurek metagabbro at 11.8 – 12.6 kbar and 480 – 565 oC, confirming the ... Bachelor Thesis Northern Sweden Uppsala University: Publications (DiVA) Vássačorru ENVELOPE(18.605,18.605,68.064,68.064) |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Scandinavian Caledonides Seve Nappe Complex Aurek metagabbro Kebnekaise Mountains Zircon U-Pb Geochronology Thermodynamic modeling Geochemistry Skandinaviska Kaledoniderna Seveskollan Kebnekaisebergen zirkon U-Pb geokronologi Termodynamisk modellering Geokemi Geology Geologi |
spellingShingle |
Scandinavian Caledonides Seve Nappe Complex Aurek metagabbro Kebnekaise Mountains Zircon U-Pb Geochronology Thermodynamic modeling Geochemistry Skandinaviska Kaledoniderna Seveskollan Kebnekaisebergen zirkon U-Pb geokronologi Termodynamisk modellering Geokemi Geology Geologi Rousku, Sabine Unraveling the Tectonic History of the Aurek Metagabbro within the Seve Nappe Complex, Scandinavian Caledonides |
topic_facet |
Scandinavian Caledonides Seve Nappe Complex Aurek metagabbro Kebnekaise Mountains Zircon U-Pb Geochronology Thermodynamic modeling Geochemistry Skandinaviska Kaledoniderna Seveskollan Kebnekaisebergen zirkon U-Pb geokronologi Termodynamisk modellering Geokemi Geology Geologi |
description |
The Scandinavian Caledonides form a mountain range comprising nappe stacks of numerous far-travelled thrust sheets. The thrust sheets consist of diverse lithologies representing pre- and synorogenic sedimentary and igneous rocks subsequently metamorphosed to various degrees, from the Late Neoproterozoic to Middle Devonian. In particular, (ultra)-high-grade metamorphic rocks have been recorded in the Seve Nappe Complex (SNC), extending >1000 km along strike of the Scandinavian Caledonides. Included in the SNC of northern Sweden is the Vássačorru Igneous Complex (VIC), consisting of bimodal magmatic suites, that formed c. 845 Ma. Fieldwork was conducted in the Kebnekaise mountains of northern Sweden, focusing on the high-grade Aurek metagabbro within the VIC of the SNC. Aurek is a key locality representing both initial stages of Iapetus Ocean formation in the Ediacaran and later stage Caledonian subduction affinities, from the collision between Laurentia and Baltica. In this study, petrological description, zircon U-Pb geochronology, mineral chemistry analysis, whole rock composition, and thermodynamic modeling was performed. Zircon U-Pb geochronology yielded protolith ages of 609±2.5 Ma, and 614±2.3 Ma, suggesting the Aurek metagabbro to not be part of the VIC, as has previously been described. The age of Aurek can instead be correlated to the Kebnekaise Dyke Swarms at c. 607 Ma, in the Kebnekaise mountains. Whole rock major and trace element data of e.g., Al2O3 (15.0 – 25.0 ppm) versus SiO2 (46.0 – 53.0 ppm), Rb (2.0 – 18.0 ppm), Zr (8.0 – 58.0 ppm) versus Y (2.7 – 18.0 ppm), Th/Yb ratio 0.25 – 2.0 and Nb/Yb ratio 1.30 – 5.14, indicate assimilation of continental crust. These major and trace element signatures show that the protolith of the Aurek metagabbro probably was emplaced in a continental rift setting in the Ediacaran. Semi-quantitative thermodynamic modeling from this study present blueschist to amphibolite facies conditions for the Aurek metagabbro at 11.8 – 12.6 kbar and 480 – 565 oC, confirming the ... |
format |
Bachelor Thesis |
author |
Rousku, Sabine |
author_facet |
Rousku, Sabine |
author_sort |
Rousku, Sabine |
title |
Unraveling the Tectonic History of the Aurek Metagabbro within the Seve Nappe Complex, Scandinavian Caledonides |
title_short |
Unraveling the Tectonic History of the Aurek Metagabbro within the Seve Nappe Complex, Scandinavian Caledonides |
title_full |
Unraveling the Tectonic History of the Aurek Metagabbro within the Seve Nappe Complex, Scandinavian Caledonides |
title_fullStr |
Unraveling the Tectonic History of the Aurek Metagabbro within the Seve Nappe Complex, Scandinavian Caledonides |
title_full_unstemmed |
Unraveling the Tectonic History of the Aurek Metagabbro within the Seve Nappe Complex, Scandinavian Caledonides |
title_sort |
unraveling the tectonic history of the aurek metagabbro within the seve nappe complex, scandinavian caledonides |
publisher |
Uppsala universitet, Institutionen för geovetenskaper |
publishDate |
2021 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-455444 |
long_lat |
ENVELOPE(18.605,18.605,68.064,68.064) |
geographic |
Vássačorru |
geographic_facet |
Vássačorru |
genre |
Northern Sweden |
genre_facet |
Northern Sweden |
op_relation |
Examensarbete vid Institutionen för geovetenskaper, 1650-6553 523 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-455444 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766146830161149952 |