Werner von Gosen

Tectonic map of the Ellesmerian and Eurekan deformation belts on Svalbard, North Greenland, and the Queen Elizabeth Islands (Canadian Arctic)

The tectonic map presented here shows the distribution of the major post-Ellesmerian and pre-Eurekan sedimentary basins, parts of the Caledonian orogen, the Ellesmerian fold-and-thrust belt, structures of the Cenozoic Eurekan deformation, and areas affected by the Eurekan overprint. The present continental margin of North America towards the Arctic Ocean between the Queen Elizabeth Islands and Northeast Greenland and the present west margin of the Barents Shelf are characterized by the Palaeozoic Ellesmerian fold-and-thrust belt, the Cenozoic Eurekan deformation, and, in parts, the Caledonian orogen. In many areas, the structural trends of the Ellesmerian and Eurekan deformations are more or less parallel, and often, structures of the Ellesmerian orogeny are affected or reactivated by the Eurekan deformation. While the Ellesmerian fold-and-thrust belt is dominated by orthogonal compression and the formation of wide fold-and-thrust zones on Ellesmere Island, North Greenland, and Spitsbergen, the Eurekan deformation is characterized by a complex network of regional fold-and-thrust belts (Spitsbergen, central Ellesmere Island), large distinct thrust zones (Ellesmere Island, North Greenland), and a great number of strike-slip faults (Spitsbergen, Ellesmere Island). The Ellesmerian fold-and-thrust belt was most probably related to the approach and docking of the Pearya Terrane (northernmost part of Ellesmere Island) and Spitsbergen against the north margin of Laurasia (Ellesmere Island/North Greenland) in the earliest Carboniferous. The Eurekan deformation was related to plate tectonic movements during the final break-up of Laurasia and the opening of Labrador Sea/Baffin Bay west, the Eurasian Basin north, and the Norwegian/Greenland seas east of Greenland.

The Eurekan deformation in the Arctic: an outline

The evolution of the Eurekan deformation zones in the Arctic is closely related to the development of the circum-Greenland plate boundaries in Early Cenozoic times (53 – 34 Ma). Mostly, the Eurekan Orogeny or deformation has been interpreted as a predominantly compressive tectonic event, but the Eurekan deformational history in the Arctic was not the result of a single tectonic episode. It rather represents a complex sequence of successive tectonic stages, which produced a number of intra-continental deformation zones with changing, sometimes opposing, lateral, oblique and convergent kinematics in the Canadian Arctic Archipelago, north and NE Greenland, and Svalbard. The interaction between the continental plates, especially in combination with the development of transform faults, resulted onshore in the formation of several complex deformation zones and areas of Eurekan deformation. The Eurekan deformation can be divided into two major tectonic stages: the first phase in the Early Eocene was dominated by orthogonal compression in the West Spitsbergen Fold-and-Thrust Belt along the west margin of the Barents Shelf and contemporaneous sinistral strike-slip tectonics along the Wegener Fault and on Ellesmere Island, whereas the second phase in the Late Eocene was characterized by dextral strike-slip and compression on Ellesmere Island and contemporaneous dextral transpression and transtension along the De Geer Fracture Zone or Hornsund Fault Complex between NE Greenland and Spitsbergen.

Proterozoic Evolution of the North Atlantic–Arctic Caledonides: Insights from Detrital Zircon Analysis of Metasedimentary Rocks from the Pearya Terrane, Canadian High Arctic

The Pearya Terrane, recognized as the only exotic terrane along the Canadian Arctic margin, includes a Neoproterozoic–early Paleozoic basinal or passive-margin metasedimentary sequence that is structurally juxtaposed with arc-related Paleozoic rocks and a metamorphic basement complex containing early Neoproterozoic orthogneiss. The Neoproterozoic siliciclastic sequence is similar to other clastic sections formed at the breakup of Rodinia, but its paleogeographic origin and crustal affinity are uncertain. Detrital zircon age spectra from seven samples reveal three groups: Group A, with numerous peaks at c. 1100–1800 Ma and the youngest population at c. 1020 Ma; Group B, defined by a dominant c. 970 Ma age peak; and Group C, with dominant peaks from c. 970–1800 Ma and a small population of c. 635–710 Ma grains. Spectra from Group A resemble data from the latest Mesoproterozoic units in Svalbard, East Greenland, and the Scandinavian Caledonides, with the ubiquitous Mesoproterozoic ages observed in all these regions compatible with derivation from the Grenville-Sveconorwegian Orogen of Laurentia and Baltica. The dominance of 930–970 Ma ages in Group B reflects input from magmatic rocks of this age in Pearya and Svalbard, while the 635–710 Ma ages observed in Group C overlap with magmatic ages observed in the Arctic Alaska–Chukotka Terrane and units in the Taimyr-Timanide region. The Neoproterozoic siliciclastic strata of the Pearya Terrane originated distal to northeastern Laurentia, in a position similar to that of the constituent terranes of Svalbard and the Eleonore Bay Supergroup of East Greenland, and they record deposition along a Neoproterozoic convergent margin active during the prolonged breakup of Rodinia.

Mesozoic structural evolution of the New Siberian Islands

Abstract The New Siberian Islands are affected by a number of Mesozoic tectonic events. The oldest event (D1a) is characterized by NW-directed thrusting within the South Anyui Suture Zone combined with north–south-trending sinistral strike-slip in the foreland during the Early Cretaceous. This compressional deformation was followed by dextral transpression along north–south-trending faults, which resulted in NE–SW shortening in the Kotelny Fold Zone (D1b). The dextral deformation can be related to a north–south-trending boundary fault zone west of the New Siberian Islands, which probably represented the Laptev Sea segment of the Amerasia Basin Transform Fault in pre-Aptian–Albian times. The presence of a transform fault west of the islands may be an explanation for the long and narrow sliver of continental lithosphere of the Lomonosov Ridge and the sudden termination of the South Anyui Suture Zone against the present Laptev Sea Rift System. The intrusion of magmatic rocks 114 myr ago was followed by NW–SE-trending sinistral strike-slip faults of unknown origin (D2). In the Late Cretaceous–Paleocene, east–west extension (D3) west of the New Siberian Islands initiated the development of the Laptev Sea Rift System, which continues until today and is largely related to the development of the Eurasian Basin.