Abstract
Multibeam bathymetric data collected in the Strait of Georgia, British Columbia, have revealed two areas of seabed disturbance, interpreted to be faults. The easterly fault zone (Fraser Delta Fault) is demarked by a pockmark chain extending along strike of a southwesterly-dipping fault offset 1 km to the northeast and having a throw of over 50 m. The pockmarks occur in a region of high sedimentation, located in the Fraser River prodelta. The eastern strait fault zone (Porlier Pass Fault) occurs within a fold of the Cretaceous Nanaimo Group. Here, a series of thrust faults displace sediments from Cretaceous to Holocene by up to 40 m with over 2 km of surface expression. Based on Holocene stratigraphic displacement in an area of significant sedimentation, these fault zones are considered to be active.
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Acknowledgements
We would like to thank the captains and crews of CCGS John P. Tully and CCGS Vector for their support in the collection of the field data. Technical support for all field operations was provided by K. Conway, B. Hill, I. Frydecky and G. Standen. K. Iwanowska and R. Franklin provided invaluable assistance in the development of the graphics, and the manuscript was improved by the critical revision of H. Gary Greene, Brian Bornhold and John Cassidy. Support for this work was through the Georgia Basin Geohazards Initiative of the Geological Survey of Canada. This is Geological Survey of Canada Publication 2003071.
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Barrie, J.V., Hill, P.R. Holocene faulting on a tectonic margin: Georgia Basin, British Columbia, Canada. Geo-Mar Lett 24, 86–96 (2004). https://doi.org/10.1007/s00367-003-0166-6
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DOI: https://doi.org/10.1007/s00367-003-0166-6
Keywords
- Holocene
- Fault Zone
- Holocene Sediment
- Foreland Basin
- Fault Slip