Comparison of Magnetic and Mössbauer Results Obtained for Palaeozoic Rocks of Hornsund, Southern Spitsbergen, Arctic

Szlachta, Karol; Michalski, Krzysztof; Brzózka, K.; Górka, B.; Gałązka-Friedman, J.

doi:10.12693/aphyspola.114.1675

Cited by 6 publications

(2 citation statements)

References 2 publications

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“…The presence of magnetite within the examined samples has also been confirmed by rock-magnetic experiments. The presence of the above ferromagnetic Fe-oxides has proven to be common in the metamorphic basement of western Spitsbergen [13][14][15]49,50]. In many thin sections, small amounts of anataze were also found ( Figure 4C).…”

Section: Mineralogical Methodsmentioning

confidence: 94%

Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard

et al. 2018

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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 southwestern 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 synto 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.

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Section: Mineralogical Methodsmentioning

confidence: 94%

Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard

et al. 2018

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“…The appearance of the latter in the Slaklidalen Fm is suggested by Mössbauer investigations (Szlachta et al . 2008). Temperatures of 525–550°C are close to the T ub max of the moderate to low Ti titanomagnetite (Dunlop & Özdemir, 1997, pp.…”

Section: Rock Magnetic Experimentsmentioning

confidence: 99%

New palaeomagnetic, petrographic and ⁴⁰Ar/³⁹Ar data to test palaeogeographic reconstructions of Caledonide Svalbard

2011

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New palaeomagnetic and petrographic data are presented from Cambrian rocks of SW Svalbard to test, for the first time, Palaeozoic reconstructions of the major terranes of Svalbard. In the course of thermal demagnetization three ChRM (characteristic remanent magnetization) components were identified, which were labelled HORNL, HORNM and HORNH, respectively, on the basis of their different unblocking temperatures. The HORNM magnetization is related to the Late Ordovician–Silurian formation of the synmetamorphic S1 foliation. The HORNM palaeopole (Φ = −18.5°, Λ = 359°, Dp/Dm = 5.8°/11.4°, Plat = 6°N) matches exactly the Silurian sectors of the Baltica–Laurentia apparent polar wander paths after the closure of Iapetus (455–415 Ma). The 450 Ma 40Ar–39Ar age determination from mica ages obtained from the broad zone of mylonites along the Billefjorden Fault Zone which separates the Central and Eastern terranes, also suggests that the two terranes were eventually amalgamated by 450 Ma. The HORNMVGP also lies very near the palaeopole derived from the Middle Proterozoic rocks of the Eastern Terrane (Ny Friesland), metamorphosed during Caledonian time, suggesting its close proximity to the study area (Central Terrane). The present study has shown that at least two of the major terranes of Svalbard, as defined by previous authors, occupied similar geographical locations by Silurian time, and the previously proposed large-scale Late Devonian left lateral displacements are not supported.

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Fifty Years of Palaeomagnetic Studies in the Institute of Geophysics, Polish Academy of Sciences

Kądziałko-Hofmokl

Werner

Kruczyk

2014

Achievements, History and Challenges in Geophysics

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Palaeo-and archaeomagnetic investigations in the Institute of Geophysics were initiated at the beginning of 1960s. The archaeomagnetic study was performed in the Geomagnetic Observatory in Hel till the mid-1980s and was resumed lately in the Warsaw laboratory. Palaeomagnetic study begun in 1963 but the palaeomagnetic group obtained necessary place for the laboratory in the Central Geophysical Observatory in the newly finished building in Belsk later in 1966. Formally, the Paleomagnetic Laboratory was established in 1972. From the very beginning, palaeomagnetic studies were accompanied by studies of magnetic properties of rocks and minerals-carriers of natural remanence and by measurements of magnetic susceptibility and its anisotropy. Therefore, the laboratory became successively equipped with the apparatus for strictly palaeomagnetic study (astatic and spinner magnetometers and demagnetizing devices) as well as with devices for rock-magnetic investigations (apparatus for thermoanalysis, system for measuring of hysteresis parameters and for study of magnetic remanence at low temperatures, torsion balance, device for study of magnetic properties under mechanical stress and temperature, device for study of alterations of magnetic minerals based on thermally stimulated emission of exo-electrons (TSEE). The last three devices have not been in use for several years. At the end of 1980s, the Institute moved to a new building and the whole laboratory was moved to Warsaw. Moving palaeomagnetic measurements to town was possible due to the replacement of spinner magnetometer by the cryogenic magnetometer SQUID, which is much more sensitive and less affected by the urban disturbances. Computer software packages that are written in the Institute or obtained from their inventors became a great help in the interpretation of experimental results. Palaeomagnetic investigations have been performed in our laboratory on rocks of various origins and age, coming from various regions of Poland and other countries often in cooperation with scientists from foreign laboratories. Numerous palaeomagnetic results that are obtained in our laboratory are in

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Comparison of Magnetic and Mössbauer Results Obtained for Palaeozoic Rocks of Hornsund, Southern Spitsbergen, Arctic

Cited by 6 publications

References 2 publications

Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard

Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard

New palaeomagnetic, petrographic and ⁴⁰Ar/³⁹Ar data to test palaeogeographic reconstructions of Caledonide Svalbard

Fifty Years of Palaeomagnetic Studies in the Institute of Geophysics, Polish Academy of Sciences

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Comparison of Magnetic and Mössbauer Results Obtained for Palaeozoic Rocks of Hornsund, Southern Spitsbergen, Arctic

Cited by 6 publications

References 2 publications

Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard

Mineralogical, Rock-Magnetic and Palaeomagnetic Properties of Metadolerites from Central Western Svalbard

New palaeomagnetic, petrographic and 40Ar/39Ar data to test palaeogeographic reconstructions of Caledonide Svalbard

Fifty Years of Palaeomagnetic Studies in the Institute of Geophysics, Polish Academy of Sciences

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New palaeomagnetic, petrographic and ⁴⁰Ar/³⁹Ar data to test palaeogeographic reconstructions of Caledonide Svalbard