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TitlePliocene landscape evolution inferred from the Iperk Sequence, offshore Banks Island, NWT
 
AuthorStashin, S; Gosse, J; Smith, I RORCID logo; Csank, A
SourceArcticNet, ASM2019 Annual Science Meeting: abstracts/ArcticNet, ASM2019 Réunion scientifique annuelle : abstracts/ArcticNet, ASM2019 Annual Science Meeting: abstracts; 2019 p. 248-249 Open
Access logo Open Access
LinksOnline - En ligne (complete volume - volume complet, PDF, 2.80 MB)
Image
Year2019
Alt SeriesNatural Resources Canada, Contribution Series 20190315
PublisherArcticNet
MeetingASM2019 - ArcticNet Annual Science Meeting; Halifax, NS; CA; December 2-5, 2019
Documentbook
Lang.English
Mediaon-line; digital
File formatpdf
ProvinceNorthwest Territories; Northern offshore region
NTS98
AreaBanks Island
Lat/Long WENS-141.0000 -124.0000 76.0000 71.0000
Subjectsmarine geology; sedimentology; stratigraphy; structural geology; geophysics; Science and Technology; Nature and Environment; Holocene; Pleistocene; Neogene; Pliocene; Miocene; geological history; erosion; depositional history; paleoclimates; paleoenvironment; depositional environment; continental margins; continental shelf; geophysical surveys; seismic surveys, marine; seismic reflection surveys; core samples; lithostratigraphy; stratigraphic correlations; structural interpretations; Iperk Sequence; Beaufort Formation; Canadian Arctic Archipelago; Canada Basin; Phanerozoic; Cenozoic; Quaternary; Tertiary
ProgramGEM2: Geo-mapping for Energy and Minerals Western Arctic-Beaufort-Northern Yukon
Released2019 12 01
AbstractDuring the Pliocene (5.3-2.6 Ma), global mean surface temperatures were approximately 2°C warmer than present. However, Arctic Pliocene local mean annual temperatures were at least 22°C warmer than today, due to a shallower latitudinal temperature gradient. We hypothesize that a thick Miocene-Pliocene regolith was readily available for erosion during global cooling in the Piacenzian, which lead to a Pan-Arctic mobilization and deposition of quartz-rich sand. The mostly Pliocene Beaufort Formation (BFm) provides a well-preserved record of dramatic landscape change during that subtle (2°C) global cooling. Today the BFm outcrops along the western Canadian Arctic Archipelago where fluvial deposits formed a contiguous coastal plain and westward thickening (up to 3 km) clastic wedge across the continental shelf and into the Canada Basin. The Miocene-Holocene Iperk Sequence (IpS), interpreted in seismic data and identified in marine petroleum exploration cores from the Beaufort Sea shelf, contains some fluvial and marine sediments that may be coeval with the BFm. Quantifying how these northern landscapes respond to large-scale climate deterioration is critical to understanding the first-order controls on sediment flux and regional marine alkalinity. For the first time, a lithostratigraphic correlation of the onshore-offshore stratigraphy has been achieved using newly available climatological and chronological constraints to help evaluate the scale of landscape response to the Piacenzian climate change. Distinct geophysical facies and unconformities observed in high resolution marine seismic reflection data from ION Geophysical Technologies form the basis for subdividing the IpS into five Pliocene sub-units and a Pleistocene-Holocene sequence. The sub-unit volume changes appear to scale with contemporaneous onshore catchment-wide average erosion rates observed in BFm and equivalent onshore units. Our results also indicate that Pliocene shorelines lie between 30 and 90 km offshore from Banks Island. Furthermore, there is no evidence of coastline-parallel faulting in M'Clure Strait which supports the hypothesis that at least some waterways of the Northwest Passage may have been climatogenic (owing to fluvial and glacial incision) instead of tectonogenic grabens. We discuss the implications of these data in relation to major transgressive sequences and landscape evolution during a period of significant climate change.
Summary(Plain Language Summary, not published)
This research examines the Banks Island offshore seismic records as a means of interpreting climatic and environmental changes that occurred during a period of rapid climate change in Arctic Canada from warm conditions in the Pliocene (5.3-2.6 million years ago) to cool conditions in the Pleistocene (younger than 2.6 million years ago) and the onset of the first glaciations.
GEOSCAN ID321058

 
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