Palaeomagnetic, rock-magnetic and mineralogical investigations of the Lower Triassic Vardebukta Formation from the southern part of the West Spitsbergen Fold and Thrust Belt
| Autor: | Geoffrey Manby, Krzysztof Michalski, Rafał Szaniawski, Krzysztof Nejbert, Katarzyna Dudzisz |
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| Rok vydání: | 2018 |
| Předmět: |
Paleomagnetism
geography geography.geographical_feature_category 010504 meteorology & atmospheric sciences Natural remanent magnetization Geochemistry Geology 010502 geochemistry & geophysics 01 natural sciences Magnetization chemistry.chemical_compound Tectonics Volcano chemistry Ferrimagnetism Fold and thrust belt 0105 earth and related environmental sciences Magnetite |
| Zdroj: | Geological Magazine. 156:620-638 |
| ISSN: | 1469-5081 0016-7568 |
| DOI: | 10.1017/s0016756817001145 |
| Popis: | Magnetic, petrological and mineralogical data from 13 sites (99 independently oriented samples) of the Lower Triassic rocks located in the SW segment of the West Spitsbergen Fold and Thrust Belt (WSFTB) are presented in order to identify the ferrimagnetic carriers and establish the origin of the natural remanent magnetization (NRM). Volcanic lithoclasts and other detrital resistive grains in which the primary magnetization might endure are present in some samples. On the other hand, petrological studies indicate that sulphide remineralization could have had an important influence on the remagnetization of these rocks. The dominant ferrimagnetic carriers are titanomagnetite and magnetite. While the titanomagnetite may preserve the primary magnetization, the magnetite is a more likely potential carrier of secondary overprints. The complex NRM patterns found in most of the samples may be explained by the coexistence and partial overlapping of components representing different stages of magnetization. Components of both polarities were identified in the investigated material. The reversal test performed on the most stable components that demagnetized above 300°C proved to be negative at the 95% confidence level at any stage of unfolding. They are better grouped, however, after 100% tectonic corrections and the most stable components are clustered in high inclinations (c. 70–80°). This suggests that at least part of the measured palaeomagnetic vectors represent a secondary prefolding magnetic overprint that originated in post-Jurassic time before the WSFTB event. Vitrinite reflectance studies show these rocks have not been subjected to any strong heating ( |
| Databáze: | OpenAIRE |
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