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TitleBeaufort Formation chronostratigraphy and Pliocene landscape evolution: new insights into the Pliocene offshore deposits
AuthorStashin, S A; Gosse, J C; Smith, I RORCID logo; Csank, A Z
SourceThe Atlantic Geoscience Society (AGS) 45th Colloquium and Annual Meeting, program with abstracts/La Société Géoscientifique de l'Atlantique, 45th Colloquium and Annual Meeting, program with abstracts; 2019 p. 54-55 Open Access logo Open Access
LinksOnline - En ligne (complete volume, PDF, 2.54 MB)
Alt SeriesNatural Resources Canada, Contribution Series 20180411
PublisherAtlantic Geoscience Society
MeetingAtlantic Geoscience Society, 45th Colloquium and Annual General Meeting; Fredericton, NB; CA; February 8-9, 2019
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®)
ProvinceNunavut; Northwest Territories; Northern offshore region
AreaCanadian Arctic Archipelago; Banks Island; Northwest Passage
Subjectsregional geology; stratigraphy; paleontology; structural geology; tectonics; environmental geology; geochronology; geophysics; Pliocene; Pleistocene; Miocene; paleoenvironment; paleoclimates; temperature; climate effects; climate, arctic; depositional environment; depositional history; sedimentation; sediment volumes; tectonic history; faulting; glacial history; biostratigraphy; geophysical interpretations; seismic interpretations; shoreline changes; oceanography; alkalinity; transgressions; Beaufort Formation; Iperk Sequence; Canada Basin; Beaufort-Mackenzie Basin; Climate change; Phanerozoic; Cenozoic; Quaternary; Tertiary
ProgramGEM2: Geo-mapping for Energy and Minerals Western Arctic Sverdrup Basin
Released2019 02 01
AbstractPliocene (2.6-5.3 Ma) global average surface temperatures were approximately 2ºC warmer than at present. However, at high latitudes, Pliocene mean annual temperatures were up to 19ºC warmer. The Beaufort Formation (BFm), currently extending along the western Canadian Arctic Archipelago, is a fluvial deposit that formed a contiguous coastal plain and westward thickening marine clastic wedge across the continental shelf and into the Canada Basin. Its eastern extent has not been established. Based on available biostratigraphy and geochronology, the BFm was deposited during the Late Miocene through Pliocene. Intervals of Pliocene continental-shelf progradation are also recorded offshore in the Iperk Sequence, a pervasive and thick package of fluvial and marine sediment in the Beaufort-Mackenzie, and Canada basins. The Iperk Sequence is considered to be Pliocene-Pleistocene, and parts of this sequence are thought to correlate with the onshore BFm. The combination of a large sediment volume (exceeding 3 km thick), the high sensitivity to climate change at this latitude, and exceptionally well-preserved sedimentary and fossil archives that capture the depositional and ecological environments, makes the BFm and Iperk Sequence among the best records for the study of landscape evolution during a large-scale climate change (such as the one currently ongoing).
Our research goals are to interpret and correlate the offshore stratigraphy and record of faulting to establish the history of sedimentation and progradation, the timing of faulting, the links with climate change, and the factors controlling the landscape response to climate change. Ultimately, we are attempting to test hypotheses regarding the maximum extent and thickness of the BFm and the tectonic or incision origin of the Northwest Passage.
Using recently acquired marine seismic imagery from ION Geophysical Technologies, we have for the first time (i) subdivided the Iperk Sequence in the offshore Banks Island region into its Pliocene-Pleistocene components, (ii) calculated sediment volumes, and (3) located the Pliocene paleo-shorelines. Additionally, we are testing the hypothesis that the straits comprising the Northwest Passage were formed by Pleistocene fluvial and glacial incision, not faulting. Knowledge of how landscapes respond to large-scale climate deterioration such as the Pliocene-Pleistocene transition is critical for understanding first-order controls on ocean alkalinity and changes in sediment flux to terrestrial and marine basins. 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 abstract for a poster presentation by M.Sc. student Sydney Stashin describes new research in the Banks Island region using offshore marine seismic stratigraphy to characterize Pliocene to Pleistocene stratigraphy. This connects to onshore research on the Pliocene Beaufort Formation, and is intended to help understand the controls and significance of the Pliocene-Pleistocene climatic deterioration and landscape evolution in the western Canadian Arctic.

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