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TitleEarly Carboniferous syn-rift sedimentation in the Sverdrup Basin (Yelverton Pass area, northern Ellesmere Island, Arctic Canada): a solution to the Okse Bay problem
AuthorBeauchamp, B; Alonso-Torres, D; Piepjohn, K; Thériault, P; Grasby, S E
SourceCircum-Arctic structural events: tectonic evolution of the Arctic margins and trans-Arctic links with adjacent orogens; by Piepjohn, K (ed.); Strauss, J V (ed.); Reinhardt, L (ed.); McClelland, W C (ed.); Geological Society of America, Special Paper vol. 541, 2018 p. 1-30, https://doi.org/10.1130/2018.2541(13)
Year2018
Alt SeriesNatural Resources Canada, Contribution Series 20170173
PublisherGeological Society of America
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceNunavut
NTS340C/09; 340C/10; 340C/15; 340C/16; 340D/05; 340D/06; 340D/10; 340D/11; 340D/12; 340D/13; 340D/14; 340D/15; 340E/02; 340E/03; 340E/04; 340E/05; 340F/01; 340F/02; 340F/08
AreaYelverton Pass; Ellesmere Island; Canadian Arctic Archipelago
Lat/Long WENS -83.0000 -75.2000 82.3333 81.3333
Subjectsstratigraphy; tectonics; sedimentology; paleontology; geochronology; structural geology; Lower Carboniferous; systematic stratigraphy; systematic palynology; geological history; tectonic history; rifting; depositional history; sedimentation; subsidence; intrusions; basins; basin evolution; clasts; clastic facies; lithofacies; lithology; provenance; source rocks; source areas; sediment transport; sediment dispersal; micropaleontology; microfossils; palynology; palynomorphs; radiometric dating; uranium lead dating; zircon dates; bedrock geology; structural features; faults; grabens; basement geology; lithostratigraphy; stratigraphic correlations; paleogeography; Sverdrup Basin; Borup Fiord Formation; Okse Bay Formation; Ellesmerian Orogen; Serpukhovian; Laurentia; Franklinian Orogen; Franklinian Basin; Crockerland; Canyon Fiord Formation; Nansen Formation; Otto Fiord Formation; Emma Fiord Formation; Bashkirian; Viséan; Inlet Head Thrust Fault; Hare Fiord Formation; Belcher Channel Formation; Eurekan Orogeny; clastic wedges; clast lithology; Phanerozoic; Paleozoic; Carboniferous; Pennsylvanian; Mississippian; Devonian
Illustrationsgeoscientific sketch maps; location maps; charts; cross-sections; tables; photographs; histograms; plots; correlation charts; 3-D models
ProgramWestern Arctic, Pearya Terrane, North Ellesmere, GEM2: Geo-mapping for Energy and Minerals
Released2018 12 21
AbstractThe unit previously mapped as the lower Upper Devonian Okse Bay Formation in the Yelverton Pass area of northern Ellesmere Island, considered indicative of syn-orogenic foreland (Devonian clastic wedge) basin deposition along the apex of the Ellesmerian Orogen, is in fact Early Carboniferous (Serpukhovian) in age and belongs to the Borup Fiord Formation of the successor Sverdrup Basin. The principal lines of evidence in favor of the original Okse Bay formational assignment were: (1) the presence of late Middle (Givetian) or early Late (Frasnian) Devonian palynomorphs; (2) a set of lithofacies presumably different from that of the Borup Fiord Formation; and (3) an angular unconformity between the so-called Okse Bay strata and overlying Pennsylvanian carbonates of the Nansen Formation. Here we demonstrate that the Devonian palynomorphs were eroded from the Devonian clastic wedge, transported for some distance, and deposited into the Sverdrup Basin in the Early Carboniferous. We also show that the units mapped as Okse Bay and Borup Fiord formations share the same clastic lithofacies assemblages, albeit in different proportions. We report the presence of Early Carboniferous palynomorphs in the uppermost part of a section assigned to the Okse Bay Formation, and show that detrital zircons contained in the middle part of the Okse Bay Formation yield dates as young as 358 Ma, thus demonstrating that the rocks that contain them are considerably younger than the assumed youngest age (Frasnian) based on palynology. We conclude that the Okse Bay Formation is the same unit as the Borup Fiord Formation and should be remapped as such. Both units are part of the same unconformity-bounded syn-rift Serpukhovian sequence that was rotated and differentially eroded prior to the widespread Pennsylvanian transgression.
The Serpukhovian sequence comprises three lithofacies assemblages: meandering stream clastic, braided stream/alluvial fan clastic, and shallow marine carbonate. These lithofacies assemblages were deposited as part of a differentially subsiding rift system likely bounded to the south by one or more master listric faults and associated footwall uplift, and to the north by hanging wall ramp uplift. The Serpukhovian sequence comprises three fourth-order sequences, each interpreted as corresponding to a rift pulse. Relatively coarse terrigenous sediments derived from the erosion of the Franklinian basement (Laurentia margin) and the Devonian clastic wedge entered the rift basin at a high angle through broad alluvial fans and braided river systems. These streams fed into a NE-flowing basin-axial meandering system, which met a shallow sea to the northeast. An additional source of sediments is Crockerland to the north, including syn- to post-Ellesmerian intrusions that shed detrital zircons of latest Devonian age once sufficient unroofing of these had occurred during the Serpukhovian.
Summary(Plain Language Summary, not published)
This work examines the age of geologic units on northern Ellesmere Island and argues that previous age assignments were incorrect. The impact of this is 1) the geologic maps of the region need to be revised to show the correct geology, and 2) points to a need for new circum-arctic correlation of similar units. These results may also change the current model for early development of the Sverdrup Basin, a major petroleum province of Canada.
GEOSCAN ID305831