Detrital zircon U-Pb geochronology is one of the most common methods used to constrain the provenance of ancient sedimentary systems. Yet, its efficacy for precisely constraining paleogeographic reconstructions is often complicated by geological, analytical, and statistical uncertainties. To test the utility of this technique for reconstructing complex, margin-parallel terrane displacements, we compiled new and previously published U-Pb detrital zircon data (n = 7924; 70 samples) from Neoproterozoic–Cambrian marine sandstone-bearing units across the Porcupine shear zone of northern Yukon and Alaska, which separates the North Slope subterrane of Arctic Alaska from northwestern Laurentia (Yukon block). Contrasting tectonic models for the North Slope subterrane indicate it originated either near its current position as an autochthonous continuation of the Yukon block or from a position adjacent to the northeastern Laurentian margin prior to >1000 km of Paleozoic–Mesozoic translation. Our statistical results demonstrate that zircon U-Pb age distributions from the North Slope subterrane are consistently distinct from the Yukon block, thereby supporting a model of continent-scale strike-slip displacement along the Arctic margin of North America. Further examination of this dataset highlights important pitfalls associated with common methodological approaches using small sample sizes and reveals challenges in relying solely on detrital zircon age spectra for testing models of terranes displaced along the same continental margin from which they originated. Nevertheless, large-n detrital zircon datasets interpreted within a robust geologic framework can be effective for evaluating translation across complex tectonic boundaries.

Quartz-in-garnet inclusion barometry integrated with trace element thermometry and calculated phase relations is applied to mylonitised schists of the Pinkie unit cropping out on the island of Prins Karls Forland (PKF), western part of the Svalbard Archipelago. This approach combines conventional and novel techniques and allows deciphering the P-T evolution of mylonitic rocks, for which the pressuretemperature conditions could not have been easily deciphered using traditional methods. The results obtained suggest that rocks of the Pinkie unit were metamorphosed under amphibolite facies conditions at 8-10 kbar and 560-630°C and mylonitised at ~ 500-550 °C and 9-11 kbar. The P-T results are coupled with in-situ Th-U-total Pb monazite dating, which record amphibolite-facies metamorphism at c. 359-355 Ma. This is the very first evidence of late Devonian-early Carboniferous metamorphism in Svalbard and it implies that the Ellesmerian Orogeny on Svalbard was associated with metamorphism up to amphibolite facies conditions. Thus, it can be concluded that the Ellesmerian collision between the Franklinian margin of Laurentia and Pearya and Svalbard caused not only commonly accepted brittle deformation and weak greenschist facies metamorphism, but also a burial and deformation of rock complexes at much greater depths at elevated temperatures.

Recent field-based studies indicate that the northern margin of North America is best interpreted as a tectonic boundary that experienced a long, complex history of strike-slip displacement. Structures juxtaposing the Pearya and Arctic Alaska terranes with North America are linked and define the Canadian Arctic transform system (CATS) that accommodated Paleozoic terrane translation, truncation of the Caledonian orogen, and shortening within the transpressional Ellesmerian orogen. The structure was reactivated during Mesozoic translational opening of the Canada Basin. Land-based evidence supporting translation along the Canadian Arctic margin is consistent with transform structures defined by marine geophysical data, thereby providing a robust alternative to the current consensus model for rotational opening of the Canada Basin.

Eocene Eurekan deformation has proven to be an enigmatic sequence of tectonic episodes dominated by tectonic plate compression and translation in the circum-Arctic region. Prins Karls Forland on western Spitsbergen is composed of Neoproterozoic siliciclastic metasediments of Laurentian affinity regionally metamorphosed to greenschist facies conditions. A crustal-scale ductile to brittle deformation zone, here named the Bouréefjellet fault zone, contains the amphibolite facies Pinkiefjellet Unit exposed between the lower metamorphic grade, upper structural unit of the Grampianfjella Group and the Scotiafjellet Group in the footwall. A preliminary age for the amphibolite facies metamorphism (ca. 360–355 Ma) indicates Ellesmerian tectonism, unlike other higher-grade basement rocks on Svalbard. Ten metasedimentary rocks from within the fault zone were collected for multiple single-grain fusion 40Ar/39Ar geochronology, with up to ten muscovite crystals dated per sample. High strain in the rocks is evinced by mylonitic structure, mica fish, and C’ shear zones, and dynamically recrystallized quartz with significant grain bulging and subgrain rotation, indicative of >350 °C temperatures. There is notable dispersion in the 40Ar/39Ar ages between samples, with single muscovite dates ranging from ca. 300 Ma to as young as 42 Ma, reflecting recrystallization and resetting of the muscovite. Younger, reproducible ages were obtained from samples that possess chemically homogeneous muscovite, yielding dates of 55–44 Ma for the Eurekan deformation on Prins Karls Forland. We suggest that Ellesmerian structures on Prins Karls Forland were reactivated during the Eocene (commencing as early as 55 Ma) progressing under warm, yet brittle, conditions that continued to 44 Ma. These 40Ar/39Ar muscovite dates are the first documented Eurekan deformation ages from Svalbard and enable a better understanding of the stages of Eurekan deformation in the Eocene to improve correlations across the circum-Arctic region.