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TitleMultifaceted re-analysis of the enigmatic Kitimat slide complex, Canada
AuthorStacey, C D; Lintern, D G; Enkin, R J
SourceSedimentary Geology vol. 369, 2018 p. 46-59, https://doi.org/10.1016/j.sedgeo.2018.01.006
Year2018
Alt SeriesNatural Resources Canada, Contribution Series 20170379
PublisherElsevier
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html; docx (Microsoft® Word®)
ProvinceBritish Columbia
NTS103H/15NE; 103I/02SE
AreaKitimat Arm; Kitimat; Kitimat River; Kitimaat Village; Minette Bay; Moon Bay; Wathl Creek
Lat/Long WENS-128.7167 -128.6167 54.0167 53.9167
Subjectsmarine geology; surficial geology/geomorphology; engineering geology; geophysics; geochronology; stratigraphy; sedimentology; marine environments; landslides; landslide deposits; tsunami; geophysical interpretations; acoustic surveys, marine; bathymetry; seismic interpretations; seismic reflection surveys; marine sediment cores; radiometric dates; radiocarbon dates; carbon-14 dates; isotopic studies; lead; depositional history; morphology; modelling; deformation; submarine ridges; flow trajectories; bedforms; shearing; pressure; submarine fans; gullies; erosion; hummocks; core analysis; lithofacies; sedimentary structures; density logging; stratigraphic analyses; Holocene; Recent; Kitimat Landslide; Kitimat Delta; geological hazards; multibeam bathymetry; Phanerozoic; Cenozoic; Quaternary
Illustrationslocation maps; geoscientific sketch maps; tables; seismic profiles; photographs; images; lithologic sections; core logs; correlation sections; profiles; models; schematic representations
ProgramMarine Geohazards, Public Safety Geoscience
Released2018 02 02
AbstractRepeat submarine landslides are challenging to study due to the tendency of subsequent slides to destroy previous deposits. Repeat slides are common in fjord head deltas where high amounts of sediment are focused in narrow valleys. This study examines a well-known slide deposit associated with the Kitimat Delta on Canada's west coast that has been linked to tsunamigenic landslides in 1974 and 1975. For the first time we incorporate multibeam bathymetry to a multifaceted dataset including new high resolution acoustic data and sediment cores to examine the history of submarine slides at the Kitimat Delta. Based on morphological analysis and age modelling using 210Pb and 14C data, we determine that the complex surface morphology of the slide lobe consists of at least two large slide deposits that reach 5 km from the delta: the known event that occurred in 1975 and an older event that occurred at 623 ± 83 cal BP (95% confidence interval). We demonstrate that slide deposits can be differentiated based on surface morphology and acoustic character. This is confirmed by age modelling. The 1975 slide resulted in a flow that ploughed through the seabed creating compression and translation along a basal shear plane, resulting in deep deformation and a surface characterized by pressure ridges. The 623 ± 83 cal BP event resulted in a large amount of blocky slide material that overran the former seafloor and was transported N5 km from the delta front. Several buried events are observed at depth, one of which occurred at 2592 ± 84 cal BP and appears to be on the same order of magnitude as the 1975 event and showing very similar acoustic characteristics. As for hazard implications, we show submarine landslides of varying sizes have naturally occurred on this delta throughout the past several thousand years.
Summary(Plain Language Summary, not published)
Repeat submarine landslides are challenging to study due to the tendency of subsequent slides to destroy the previous deposits. Repetitive slides are common in fjord head deltas where high amounts of sediment are focused in narrow valleys. This study examines a well-known slide deposit associated with the Kitimat Delta on Canada¿s West Coast that has been linked to tsunamigenic landslides in 1974 and 1975. Using new acoustic technology we re-examine the history of slides on the Kitimat Delta. Through radiometric dating of sediment cores we demonstrate that there is a much longer history of large landslides than was previously understood. Two older slides occurred approximately 673 and 2642 years ago that were both comparable in size to the 1975 event that triggered a tsunami. We describe the depositional styles of the different slides. The hazard implications from this study are that large slides have occurred naturally on this delta throughout the past several thousand years.
GEOSCAN ID308050