Circum-Arctic Structural Events: Tectonic Evolution of the Arctic Margins and Trans-Arctic Links with Adjacent Orogens

The circum-Arctic region has received considerable attention over the past several decades with vigorous debate focused on topics such as mechanisms for opening the Eurasian and Amerasian basins, the importance of plume-related magmatism in the development of the Arctic Ocean, and mechanisms for ancient terrane translation along the Arctic margins. In recognition of the 25th anniversary of the Circum-Arctic Structural Events (CASE) program, an international polar research effort organized and led by the Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) of Germany, this volume presents results from 18 major field expeditions involving over 100 international geoscientists from a broad spectrum of disciplines. The resulting publication focuses on the Proterozoic to Cenozoic tectonic evolution of the circum-Arctic region with correlations to adjacent orogens.
Early Carboniferous syn-rift sedimentation in the Sverdrup Basin (Yelverton Pass area, northern Ellesmere Island, Arctic Canada): A solution to the Okse Bay problem
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Published:June 14, 2019
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CiteCitation
B. Beauchamp, D. Alonso-Torres, K. Piepjohn, P. Thériault, S.E. Grasby, 2019. "Early Carboniferous syn-rift sedimentation in the Sverdrup Basin (Yelverton Pass area, northern Ellesmere Island, Arctic Canada): A solution to the Okse Bay problem", Circum-Arctic Structural Events: Tectonic Evolution of the Arctic Margins and Trans-Arctic Links with Adjacent Orogens, Karsten Piepjohn, Justin V. Strauss, Lutz Reinhardt, William C. McClelland
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ABSTRACT
The 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.
- Arctic region
- basins
- Canada
- Carboniferous
- clastic wedges
- deformation
- depositional environment
- Devonian
- Ellesmere Island
- Ellesmerian Orogeny
- fluvial environment
- Frasnian
- intermontane basins
- lithofacies
- lithostratigraphy
- Lower Carboniferous
- marine environment
- microfossils
- Mississippian
- nesosilicates
- Nunavut
- orthosilicates
- Paleozoic
- palynomorphs
- plate tectonics
- pull-apart basins
- Queen Elizabeth Islands
- rifting
- sedimentation
- sequence stratigraphy
- Serpukhovian
- silicates
- Sverdrup Basin
- syntectonic processes
- tectonics
- thermal maturity
- U/Pb
- Upper Devonian
- Upper Mississippian
- zircon
- zircon group
- Eurekan Orogeny
- Franklinian Basin
- Belcher Channel Formation
- Canyon Fiord Formation
- detrital zircon
- Okse Bay Formation
- Borup Fiord Formation
- Yelverton Pass