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

Abstract

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.

U‐Pb zircon dating of metaigneous rocks from the Nordbreen Nappe of Svalbard’s Ny‐Friesland suggests their affinity to Northeast Greenland

“…The Eastern Basement Province is separated from the other provinces by a large strike‐slip shear zone called the Billefjorden Fault Zone (e.g. Gee & Tebenkov, ; Harland, ; Michalski, Lewandowski, & Manby, ; Figure ), while the boundary between the Northwestern and Southwestern Basement Provinces is marked by the front of the West Spitsbergen Fold and Thrust Belt (Dallmann, Andresen, Bergh, Maher, & Ohta, ; Harland & Horsfield, ).…”

Applying the anisotropy of magnetic susceptibility technique to the study of the tectonic evolution of the West Spitsbergen Fold-and-Thrust Belt

“…The extent to which the western ProterozoicÁEarly Paleozoic basement blocks exhibit the same degree and character of Eurekan deformation is still a matter of debate (e.g., Dallmann 1992;Tessensohn 2001;Thiedig et al 2001;Michalski et al 2012).…”

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

“…The palaeomagnetic study in polar regions led earlier by Maria Jeleńska and (Michalski et al 2012). From 2012 he is the leader of the project ''Integration of palaeomagnetic, isotopic and structural data to understand Svalbard Caledonian Terranes assemblage (2012)(2013)(2014)(2015)'' funded by Polish National Science Centre.…”