The Nagssugtoqidian Orogen of West Greenland represents a belt of Palaeoproterozoic deformation and metamorphism between the North Atlantic Craton of South Greenland and a northern, lesser known continental segment that includes the Rinkian Orogen. First-order observations are interpreted to support a cycle of separation, convergence, and eventual collision of two continental masses. The emplacement of the Kangâmiut dyke swarm marked the onset of continental breakup at ca. 2040 Ma, and sedimentary basins formed between ca. 1950 and 1920 Ma. Subsequent convergence and consumption of an oceanic plate caused arc magmatism at 1920–1870 Ma. Granulite-facies peak metamorphism at 1860–1840 Ma in the centre of the orogen is related to crustal thickening by WNW-directed thrusting. Large-scale, upright folding with an east–west trend was ongoing by 1825 Ma. Sinistral strike-slip movement was concentrated along steeply dipping limbs of these large-scale folds and formed orogen-scale steep belts at ca. 1775 Ma. Close similarities between the northern and southern foreland suggest that the two cratons likely originated from one continuous continental block. Temporal and kinematic correlation of these events with adjoining orogens in Canada and Greenland shows close genetic links. The Nagssugtoqidian Orogen of West Greenland continues eastwards beneath the Greenland Ice cap to the Eastern Nagssugtoqidian belt of East Greenland (a.k.a. the Ammassalik belt). The Torngat Orogen of eastern Canada developed simultaneous with the Nagssugtoqidian Orogen with a kinematic compatibility suggesting that the two orogens formed on the west and north flanks, respectively, of a curved leading continental margin of an indenting North Atlantic Craton.

Based on available tectonostratigraphic, geochronological,

The complex Ungava fault zone lies in the Davis Strait and separates failed spreading centres in the Labrador Sea and Baffin Bay. This study focuses on coastal exposures east of the fault-bound Sisimiut basin, where the onshore expressions of these fault systems and the influence of pre-existing basement are examined. Regional lineament studies identify five main systems: N–S, NNE–SSW, ENE–WSW, ESE–WNW and NNW–SSE. Field studies reveal that strike-slip movements predominate, and are consistent with a ~NNE–SSW-oriented sinistral wrench system. Extensional faults trending N–S and ENE–WSW (basement-parallel), and compressional faults trending E–W, were also identified. The relative ages of these fault systems have been interpreted using cross-cutting relationships and by correlation with previously identified structures. A two-phase model for fault development fits the development of both the onshore fault systems observed in this study and regional tectonic structures offshore. The conclusions from this study show that the fault patterns and sense of movement on faults onshore reflect the stress fields that govern the opening of the Labrador Sea – Davis Strait – Baffin Bay seaway, and that the wrench couple on the Ungava transform system played a dominant role in the development of the onshore fault patterns.

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Dawes, P. R., Frisch, T., Garde, A. A., Iannelli, T. R., Ineson, J. R., Jensen, S. M., Pirajno, F., Sønderholm, M., Stemmerik, L., Stouge, S., Thomassen, B., & van Gool, J. A. (2000). Kane Basin 1999: mapping, stratigraphic studies and economic assessment of Precambrian and Lower Palaeozoic provinces in north-western Greenland. Geology of Greenland Survey Bulletin, 186, 11-28. https://doi.org/10.34194/ggub.v186.5211 _______________ The geological map coverage of Greenland at scale 1:500 000 is nearing completion, with the Kane Basin sheet of north-western Greenland the last to be compiled (sheet 6 between 78°–81°N; Fig. 1). Sporadic work by the Survey since the 1970s identified the main geological provinces and structure of the region but the lithologies of the Precambrian shield were not sufficiently mapped inland to warrant final compilation. Project Kane Basin 1999 was designed to provide this knowledge; the optimal use of logistics enabled a range of geological activities to be undertaken, as well as other scientific disciplines.

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