Faults and fractures in central West Greenland: onshore expression of continental break-up and sea-floor spreading in the Labrador – Baffin Bay Sea

Authors

  • Robert W. Wilson Reactivation Research Group, Department of Earth Sciences, University of Durham, Durham DH1 3LE, UK
  • Knud Erik S. Klint Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark
  • Jeroen A.M. van Gool Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark
  • Kenneth J.W. McCaffrey Reactivation Research Group, Department of Earth Sciences, University of Durham, Durham DH1 3LE, UK
  • Robert E. Holdsworth Reactivation Research Group, Department of Earth Sciences, University of Durham, Durham DH1 3LE, UK
  • James A. Chalmers Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark

DOI:

https://doi.org/10.34194/geusb.v11.4931

Keywords:

faults and fractures, extensional tectonics, wrench systems, sedimentary basins, basement reactivation, West Greenland

Abstract

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.

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Published

2006-12-05

How to Cite

Wilson, R. W. ., Klint, K. E. S. ., van Gool, J. A. ., McCaffrey, K. J. ., Holdsworth, R. E. ., & Chalmers, J. A. . (2006). Faults and fractures in central West Greenland: onshore expression of continental break-up and sea-floor spreading in the Labrador – Baffin Bay Sea. GEUS Bulletin, 11, 185–204. https://doi.org/10.34194/geusb.v11.4931