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

Abstract

SIMS U-Pb zircon dating of metaigneous rocks of the Nordbreen Nappe from the West Ny-Friesland terrane (Eastern Basement Province of Svalbard) yields crystallization ages of 1,761 ± 4 Ma for a felsic metatuff and 1,373 ± 4 Ma for a metagabbro dyke. The Palaeoproterozoic age of the metatuff is similar to previously obtained ages for various felsic rocks from the study area, whereas the Mesoproterozoic age of the metagabbro has not been thus far documented on Svalbard. However, a similar age pattern has been reported from Northeast Greenland. Therefore, we conclude that the West Ny-Friesland terrane can be correlated with age equivalent units of Northeast Greenland. We also explore similarities and dissimilarities between the study area and other terranes of Svalbard and speculate on regional-scale correlations. Together, the presented new ages provide critical piercing points in palaeogeographic reconstructions of the relatively poorly understood circum-Arctic region. | 519BAZARNIK et Al.

Timing of Paleozoic Exhumation and Deformation of the High-Pressure Vestgӧtabreen Complex at the Motalafjella Nunatak, Svalbard

“…Therefore, two different styles of tectonic transport were active as strike-slip shear zones in Svalbard/Pearya and predominant thrusting in the Scandinavian Caledonides during the Silurian to Early Devonian. These mechanics strongly resemble the idea of escape tectonics, which has been previously discussed for the Vestgötabreen Complex and the Svalbard basement provinces [2,19,31,85]. Although this hypothesis has been previously discussed, the correlative unit(s) within the Scandinavian Caledonides have not.…”

“…The crystalline rocks on Svalbard record a multi-phase deformational history that was recorded in three Caledonian Basement Provinces that were amalgamated along major strike-slip boundaries during the Caledonian Orogeny (Figure 1) [1,2,7,8,[17][18][19]. Within these provinces, two prominent Paleozoic tectonic events were recorded: (1) the late Cambrian to Early Devonian Caledonian Orogeny, and (2) the Late Devonian to early Carboniferous Ellesmerian Orogeny.…”

Provenance Analysis of the Andrée Land Basin and Implications for the Paleogeography of Svalbard in the Devonian

“…The two terranes are separated by the Eolussletta Shear Zone (Figure 1b; Lyberis & Manby, 1999; Manby, 1990; Manby & Lyberis, 1992; Manby et al., 1994) or the “Veteranen Line” (Harland et al., 1992, 1997). The Western Ny‐Friesland terrane contains the oldest rocks of Svalbard, with Paleoproterozoic high‐grade metamorphic complexes of orthogneiss, migmatite and amphibolite intruded by granitoids and felsic meta‐tuff with ages of c. 1750 and 1760 Ma (Bazarnik et al., 2019; Dallmann, 2015). The Mosselhalvøya Unit is characterized by Mesoproterozoic medium‐ to high‐grade metamorphic supracrustal and igneous rocks previously referred to as the Planetfjella Group (Wallis, 1967).…”

“…On both the eastern and western sides of the Devonian Andrée Land Basin, Caledonian deformation is characterized by E-W shortening, folding, cleavage-formation, and metamorphism (Harland et al, 1997). On Biscayarhalvøya and northern Ny-Friesland (Figure 1b), west-directed thrust sheets or nappe stacks are reported (e.g., Bazarnik et al, 2019;Hellman et al, 2001;Labrousse et al, 2008;Witt-Nilsson et al, 1998). In a late stage of the Caledonian orogeny, the basement areas on both provinces were affected by intrusion of syn-tectonic granites and migmatization (Johansson et al, 2002(Johansson et al, , 2004.…”

Early Devonian sinistral shearing recorded by retrograde monazite-(Ce) in Oscar II Land, Svalbard

“…The provinces themselves have a composite structure and several internal tectonic boundaries that separate crustal blocks with a dissimilar geological record (e.g. Bazarnik et al 2019;Gasser, Andersen 2013;Gee, Teben'kov 2004;Mazur et al 2009;Wala et al 2021). The Eastern Basement Province (EBP) and the Northwestern Basement Province (NBP) are separated by the Billefjorden Fault zone -the N-S trending transcurrent sinistral strike-slip zone dated to ca.…”