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TitleIchnology and sedimentology of Cretaceous and Paleogene strata on Bylot Island, Nunavut: development of a rift-basin succession in Baffin Bay
AuthorDafoe, L TORCID logo; Haggart, J
SourceThe Atlantic Geoscience Society (AGS), 44th Colloquium and Annual Meeting, program with abstracts/La Société Géoscientifique de l'Atlantique, 44th Colloquium and Annual Meeting, program with abstracts; 2018 p. 19-20 Open Access logo Open Access
LinksOnline - En ligne (complete volume - volume complet, 1.39 MB)
Alt SeriesNatural Resources Canada, Contribution Series 20190140
PublisherAtlantic Geoscience Society
Meeting44th Atlantic Geoscience Society Colloquium and Annual Meeting; Truro, NS; CA; February 2-3, 2018
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®)
ProvinceNunavut; Northern offshore region
NTS38A; 38B; 38C; 38D; 48D
AreaBylot Island; Maud Bight; Baffin Bay; Baffin Island; Salmon River
Lat/Long WENS -81.0000 -72.0000 74.0000 72.5000
Subjectsstratigraphy; paleontology; sedimentology; tectonics; Paleogene; Eocene; Paleocene; trace fossils; ichnology; ichnofacies; tectonic setting; tectonic history; basin evolution; rifting; sea floor spreading; bedrock geology; sedimentary rocks; mudstones; shales; sandstones; conglomerates; siltstones; structural features; grabens; lithology; sedimentary rocks; depositional history; depositional environment; paleoenvironment; sedimentary structures; sedimentation rates; Labrador-Baffin Seaway; North American Plate; North Bylot Trough; Eclipse Trough; Diplocraterion; Scoyenia; Phycosiphon; Zoophycos; Cruziana; Macaronichnus; Phanerozoic; Cenozoic; Tertiary; Mesozoic; Cretaceous
ProgramGEM2: Geo-mapping for Energy and Minerals Baffin Mapping of onshore Cretaceous Strats
Released2018 02 01
AbstractThe Labrador-Baffin Seaway formed during rifting and separation of Greenland from the North American plate. Rifting began in the Early Cretaceous, with seafloor spreading starting in the Maastrichtian and ending in late Eocene. As a result, Early Cretaceous syn-rift strata accumulated in grabens, followed by late rift and post-rift deposition. Bylot Island, at the northwestern end of Baffin Bay, preserves a record of this rift history, providing a vital analogue for understanding the adjacent offshore succession. Cretaceous and Paleocene strata are preserved today on north Bylot Island at Maud Bight (North Bylot Trough) and on southwest Bylot Island and nearby areas of Baffin Island (Eclipse Trough). Our detailed analysis of the ichnology and sedimentology of 14 measured stratigraphic sections from these areas provides new insights into the depositional paleoenvironments of these strata. Lower Cretaceous syn-rift strata of Eclipse Trough are well preserved along Salmon River on Baffin Island. Basal deposits reflect alternating aquatic conditions and subaerial exposure, including wave, interference, and adhesion ripples, mud crack casts, and plane-bed lineations. Surface trails, arthropod trackways, and Diplocraterion comprise a Scoyenia Ichnofacies and with the sedimentology suggest deposition within a lake-margin or floodplain setting. The uppermost of these strata are fluvial, with shallow channels, coals, and overbank mudstones. Overlying these beds in both Eclipse and North Bylot Troughs, an Upper Cretaceous transgressive shale is characteristically dominated by Phycosiphon, forming an assemblage of the Zoophycos Ichnofacies and interpreted as representing outer shelf (or more distal) deposits. Higher Upper Cretaceous sandstones in Eclipse Trough record progradational cycles of storm-dominated, inner shelf through foreshore deposits, with cross-stratified beds alternating with bioturbated fair-weather beds containing diverse and abundant archetypal Cruziana Ichnofacies suites. At Maud Bight, probable Upper Cretaceous sandstones also reflect storm-dominated, lower shoreface to upper shoreface, hummocky to tabular cross-stratified beds alternating with fair-weather beds, characteristically bioturbated by Macaronichnus. Similar storm-dominated shoreface strata are seen in Paleocene sandstones from Eclipse Trough; however, more thickly-bedded sandstones there show evidence of high sedimentation rates, suggesting deltaic deposition. In Maud Bight, probable Paleocene sandstones and conglomerates reflect delta-front deposition, in addition to fine-grained, grey, Macaronichnus-dominated shoreface to foreshore sandstones. Overlying the Paleocene sandstones in Maud Bight, interbedded shales, siltstones, and sandstones reflect shallow, brackish deposition within an estuarine or prodeltaic setting. The overall succession is predominantly marine with common storm-dominance and similar depositional paleoenvironments seen between the two structurally isolated areas of Bylot Island.
Summary(Plain Language Summary, not published)
The Cretaceous and Paleogene onshore stratigraphy of Bylot Island, Nunavut provides a vital analogue for understanding the adjacent offshore succession in Baffin Bay where sampling is very limited. Detailed analysis of the sedimentology and trace fossils of 14 previously measured stratigraphic sections provides new insights into the depositional paleoenvironments of the rock units. Specifically, the overall succession shows a predominance of marine deposition and storm-dominance with similar depositional paleoenvironments seen between the two structurally isolated areas of Bylot Island.

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