Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard
A combination of mineralogical, rock-magnetic and palaeomagnetic methods were employed in an attempt to shed a new light on the tectonism and paleogeography of Central Western Svalbard. The focus is on six metadolerite sites from the metamorphic Proterozoic–Lower Palaeozoic complex of south-western...
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ftmdpi:oai:mdpi.com:/2075-163X/8/7/279/ 2023-08-20T04:04:48+02:00 Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard Mariusz Burzyński Krzysztof Michalski Geoffrey Manby Krzysztof Nejbert agris 2018-06-29 application/pdf https://doi.org/10.3390/min8070279 EN eng Multidisciplinary Digital Publishing Institute Mineral Geochemistry and Geochronology https://dx.doi.org/10.3390/min8070279 https://creativecommons.org/licenses/by/4.0/ Minerals; Volume 8; Issue 7; Pages: 279 magnetic mineralogy rock-magnetic experiments palaeomagnetism Arctic Western Spitsbergen Text 2018 ftmdpi https://doi.org/10.3390/min8070279 2023-07-31T21:36:08Z A combination of mineralogical, rock-magnetic and palaeomagnetic methods were employed in an attempt to shed a new light on the tectonism and paleogeography of Central Western Svalbard. The focus is on six metadolerite sites from the metamorphic Proterozoic–Lower Palaeozoic complex of south-western Oscar II Land (Western Spitsbergen). The primary mineral compositions of the metadolerites were strongly remineralized during Caledonian (sensu lato) greenschist-facies metamorphism although some younger tectonothermal modification is also apparent from the rock-magnetic studies. Rock-magnetic experiments supported by thin-section mineral identification and separation of Fe-containing fractions indicate that the main ferromagnetic carriers of the Natural Remanent Magnetization are represented by low-coercivity pyrrhotite and magnetite/maghemite. The investigated metadolerites are characterized by complex pattern of magnetization. The low-temperature palaeomagnetic components which demagnetized up to 250 °C, are characterized by high inclinations (~70–80°) potentially representing Mesozoic–Cenozoic remagnetization. The most stable middle-high temperature directions which demagnetized from 250 °C, were obtained from only two of six sites. Two Virtual Geomagnetic Poles calculated from two of the middle-high temperature site means do not correlate with the Laurussia reference path for syn- to post-Caledonian time. Two possible explanations of observed inconsistency are discussed. These are a modification of the Oscar II Land Caledonian basement geometry by listric faulting and/or tectonic rotations related to Daudmannsdalen–Protectorbreen high-strain (shear) zone. The results presented here suggest that post-Caledonian tectonic modification of the palaeomagnetic directions may be more a widespread feature of Western Svalbard. Text Arctic Oscar II Land Svalbard Spitsbergen MDPI Open Access Publishing Arctic Svalbard Oscar II ENVELOPE(-62.500,-62.500,-65.750,-65.750) Oscar II Land ENVELOPE(13.299,13.299,78.441,78.441) Minerals 8 7 279 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
magnetic mineralogy rock-magnetic experiments palaeomagnetism Arctic Western Spitsbergen |
spellingShingle |
magnetic mineralogy rock-magnetic experiments palaeomagnetism Arctic Western Spitsbergen Mariusz Burzyński Krzysztof Michalski Geoffrey Manby Krzysztof Nejbert Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard |
topic_facet |
magnetic mineralogy rock-magnetic experiments palaeomagnetism Arctic Western Spitsbergen |
description |
A combination of mineralogical, rock-magnetic and palaeomagnetic methods were employed in an attempt to shed a new light on the tectonism and paleogeography of Central Western Svalbard. The focus is on six metadolerite sites from the metamorphic Proterozoic–Lower Palaeozoic complex of south-western Oscar II Land (Western Spitsbergen). The primary mineral compositions of the metadolerites were strongly remineralized during Caledonian (sensu lato) greenschist-facies metamorphism although some younger tectonothermal modification is also apparent from the rock-magnetic studies. Rock-magnetic experiments supported by thin-section mineral identification and separation of Fe-containing fractions indicate that the main ferromagnetic carriers of the Natural Remanent Magnetization are represented by low-coercivity pyrrhotite and magnetite/maghemite. The investigated metadolerites are characterized by complex pattern of magnetization. The low-temperature palaeomagnetic components which demagnetized up to 250 °C, are characterized by high inclinations (~70–80°) potentially representing Mesozoic–Cenozoic remagnetization. The most stable middle-high temperature directions which demagnetized from 250 °C, were obtained from only two of six sites. Two Virtual Geomagnetic Poles calculated from two of the middle-high temperature site means do not correlate with the Laurussia reference path for syn- to post-Caledonian time. Two possible explanations of observed inconsistency are discussed. These are a modification of the Oscar II Land Caledonian basement geometry by listric faulting and/or tectonic rotations related to Daudmannsdalen–Protectorbreen high-strain (shear) zone. The results presented here suggest that post-Caledonian tectonic modification of the palaeomagnetic directions may be more a widespread feature of Western Svalbard. |
format |
Text |
author |
Mariusz Burzyński Krzysztof Michalski Geoffrey Manby Krzysztof Nejbert |
author_facet |
Mariusz Burzyński Krzysztof Michalski Geoffrey Manby Krzysztof Nejbert |
author_sort |
Mariusz Burzyński |
title |
Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard |
title_short |
Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard |
title_full |
Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard |
title_fullStr |
Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard |
title_full_unstemmed |
Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard |
title_sort |
mineralogical, rock-magnetic and palaeomagnetic properties of metadolerites from central western svalbard |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2018 |
url |
https://doi.org/10.3390/min8070279 |
op_coverage |
agris |
long_lat |
ENVELOPE(-62.500,-62.500,-65.750,-65.750) ENVELOPE(13.299,13.299,78.441,78.441) |
geographic |
Arctic Svalbard Oscar II Oscar II Land |
geographic_facet |
Arctic Svalbard Oscar II Oscar II Land |
genre |
Arctic Oscar II Land Svalbard Spitsbergen |
genre_facet |
Arctic Oscar II Land Svalbard Spitsbergen |
op_source |
Minerals; Volume 8; Issue 7; Pages: 279 |
op_relation |
Mineral Geochemistry and Geochronology https://dx.doi.org/10.3390/min8070279 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/min8070279 |
container_title |
Minerals |
container_volume |
8 |
container_issue |
7 |
container_start_page |
279 |
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1774715200571703296 |