Geophysical Data from Norrbotten, Sweden - Evidence for the Presence of a Crustal Scale Fault?
The method of combining multiple geophysical, geological, or geochemical datasets can reveal patterns of otherwise hidden features in the Earth’s crust. This may aid in geological mapping, locating economic mineral deposits and for general anomaly/feature detection. In this study a multidimensional...
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Luleå tekniska universitet, Geovetenskap och miljöteknik
2022
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ftluleatu:oai:DiVA.org:ltu-91966 2023-05-15T17:45:08+02:00 Geophysical Data from Norrbotten, Sweden - Evidence for the Presence of a Crustal Scale Fault? Markström, Jimmy 2022 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-91966 eng eng Luleå tekniska universitet, Geovetenskap och miljöteknik http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-91966 info:eu-repo/semantics/openAccess Self-Organizing Maps Magnetic Anomaly Radioisotopes Geological Faults Geochemistry Geokemi Geology Geologi Student thesis info:eu-repo/semantics/bachelorThesis text 2022 ftluleatu 2022-10-25T20:58:42Z The method of combining multiple geophysical, geological, or geochemical datasets can reveal patterns of otherwise hidden features in the Earth’s crust. This may aid in geological mapping, locating economic mineral deposits and for general anomaly/feature detection. In this study a multidimensional geophysical approach implementing five geophysical datasets is applied using Self-Organizing Maps (SOM), where the main objective is to locate and understand a previously unknown hypothesized fault in Norrbotten, Sweden. The fault is estimated to extend from the Finnish border in the north, across northern Sweden in the N-S direction at a hypothesized length of > 250 km. Self-Organizing Maps is an unsupervised neural network - originally developed by Finnish physicist Teuvo Kohonen - capable of combining any number of datasets and thereby visualize them on a simple two-dimensional map. The datasets used in the analysis were three magnetic derivatives for the x, y and z components, as well as gamma-ray intensity measurements of the 238U, 40K and 232Th radioisotopes. All these variables have been shown to be effective tools for bedrock mapping and geological feature detection and were hence chosen based on these properties. The results revealed the efficiency of the SOM analysis to represent multivariate data on a 2D plane and proved to be a generally good visualization tool for multiple geophysical datasets. There seems to be a relatively sharp difference in geophysical properties between the eastern and western blocks divided by the hypothesized fault, which may indicate the presence of this crustal scale structure. Despite the evidence found in this study, more investigations are needed to verify the existence and nature of the fault, and the results shown here may motivate further projects by providing indications and suggestive evidence for its presence. Bachelor Thesis Northern Sweden Norrbotten Luleå University of Technology Publications (DiVA) |
institution |
Open Polar |
collection |
Luleå University of Technology Publications (DiVA) |
op_collection_id |
ftluleatu |
language |
English |
topic |
Self-Organizing Maps Magnetic Anomaly Radioisotopes Geological Faults Geochemistry Geokemi Geology Geologi |
spellingShingle |
Self-Organizing Maps Magnetic Anomaly Radioisotopes Geological Faults Geochemistry Geokemi Geology Geologi Markström, Jimmy Geophysical Data from Norrbotten, Sweden - Evidence for the Presence of a Crustal Scale Fault? |
topic_facet |
Self-Organizing Maps Magnetic Anomaly Radioisotopes Geological Faults Geochemistry Geokemi Geology Geologi |
description |
The method of combining multiple geophysical, geological, or geochemical datasets can reveal patterns of otherwise hidden features in the Earth’s crust. This may aid in geological mapping, locating economic mineral deposits and for general anomaly/feature detection. In this study a multidimensional geophysical approach implementing five geophysical datasets is applied using Self-Organizing Maps (SOM), where the main objective is to locate and understand a previously unknown hypothesized fault in Norrbotten, Sweden. The fault is estimated to extend from the Finnish border in the north, across northern Sweden in the N-S direction at a hypothesized length of > 250 km. Self-Organizing Maps is an unsupervised neural network - originally developed by Finnish physicist Teuvo Kohonen - capable of combining any number of datasets and thereby visualize them on a simple two-dimensional map. The datasets used in the analysis were three magnetic derivatives for the x, y and z components, as well as gamma-ray intensity measurements of the 238U, 40K and 232Th radioisotopes. All these variables have been shown to be effective tools for bedrock mapping and geological feature detection and were hence chosen based on these properties. The results revealed the efficiency of the SOM analysis to represent multivariate data on a 2D plane and proved to be a generally good visualization tool for multiple geophysical datasets. There seems to be a relatively sharp difference in geophysical properties between the eastern and western blocks divided by the hypothesized fault, which may indicate the presence of this crustal scale structure. Despite the evidence found in this study, more investigations are needed to verify the existence and nature of the fault, and the results shown here may motivate further projects by providing indications and suggestive evidence for its presence. |
format |
Bachelor Thesis |
author |
Markström, Jimmy |
author_facet |
Markström, Jimmy |
author_sort |
Markström, Jimmy |
title |
Geophysical Data from Norrbotten, Sweden - Evidence for the Presence of a Crustal Scale Fault? |
title_short |
Geophysical Data from Norrbotten, Sweden - Evidence for the Presence of a Crustal Scale Fault? |
title_full |
Geophysical Data from Norrbotten, Sweden - Evidence for the Presence of a Crustal Scale Fault? |
title_fullStr |
Geophysical Data from Norrbotten, Sweden - Evidence for the Presence of a Crustal Scale Fault? |
title_full_unstemmed |
Geophysical Data from Norrbotten, Sweden - Evidence for the Presence of a Crustal Scale Fault? |
title_sort |
geophysical data from norrbotten, sweden - evidence for the presence of a crustal scale fault? |
publisher |
Luleå tekniska universitet, Geovetenskap och miljöteknik |
publishDate |
2022 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-91966 |
genre |
Northern Sweden Norrbotten |
genre_facet |
Northern Sweden Norrbotten |
op_relation |
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-91966 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766147901385342976 |