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TitleEarly Ordovician to Early Devonian tectonic development of the northern margin of Laurentia, Canadian Arctic Islands
AuthorDewing, KORCID logo; Hadlari, TORCID logo; Pearson, D G; Matthews, W
SourceGeological Society of America Bulletin 2019 p. 1-20,
Alt SeriesEarth Sciences Sector, Contribution Series 20160081
PublisherGeological Society of America
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html
NTS29; 38; 39; 47; 48; 49; 57; 58; 59; 67; 68; 69; 77; 78; 79; 87; 88; 89; 97; 98; 99; 120; 340; 560
AreaCanadian Arctic Archipelago; Ellesmere Island; Axel Heiberg Island; Devon Island; Baffin Island; Brodeur Peninsula; Somerset Island; Cornwallis Island
Lat/Long WENS-128.0000 -52.0000 84.0000 70.0000
Subjectstectonics; stratigraphy; paleontology; geochronology; geophysics; geochemistry; tectonic evolution; tectonic history; unconformities; subsidence; deposition; sedimentation rates; geodynamics; crustal thickness; orogenies; subduction; downgoing slab; faulting; volcanism; deformation; basins; continental margins; plate margins; bedrock geology; structural features; faults; faults, normal; folds; grabens; lithology; sedimentary rocks; shales; cherts; carbonates; evaporites; gypsum; limestones; sandstones; conglomerates; dolostones; clastics; breccias; igneous rocks; volcanic rocks; facies; flysch; paleogeography; radiometric dating; uranium lead dating; zircon dates; neodymium samarium dates; neodymium geochemistry; geophysical logging; drillholes; fossils; faunas; provenance; geophysical interpretations; seismic interpretations; wells; Laurentian Margin; Laurentia; Pearya Terrane; M'Clintock Orogeny; Irene Bay Formation; Boothis Fold Belt; Clements Markham Belt; Hazen Trough; Bay Fiord Formation; Cape Phillips Formation; Eleanor RIver Formation; Thumb Mountain Formation; Hazen Formation; Svartevaeg Formation; Franklinian Margin; Stallworthy Formation; Baumann Fiord Formation; Cape de Bray Formation; Phanerozoic; Paleozoic; Devonian; Silurian; Ordovician; Precambrian; Proterozoic
Illustrationsgeoscientific sketch maps; schematic cross-sections; geochronological charts; correlation sections; location maps; tables; seismic profiles; aerial photographs; lithologic sections; geophysical logs; profiles; stratigraphic charts; histograms; graphs
ProgramGEM2: Geo-mapping for Energy and Minerals Western Arctic Sverdrup Basin
Released2019 02 06
AbstractThree tectonic events affected the northern margin of Laurentia between Early Ordovician and Early Devonian time. Each tectonic cycle started with an unconformity followed by rapid subsidence and an influx of clastic material, then decreasing sediment accumulation rates. The first cycle extends from the Tremadoc to late Katian (480-448 Ma), the second from late Katian to Ludlow (448-426 Ma), and the third from Ludlow to Lochkovian (426-410 Ma).
A strong geodynamic link is interpreted between the first two sedimentary cycles and tectonic events on the composite Pearya terrane on northern Ellesmere Island, Nunavut, Canada. The first cycle is interpreted as a response to crustal thickening caused by the M'Clintock Orogeny on Pearya terrane and onset of subduction dipping under Laurentia. An extensive Middle Ordovician (Darriwillian) unconformity is not associated with a change in subsidence rate or a change of facies above and below, but is normally faulted. It is interpreted as a migrating forebulge or increase in crustal buoyancy due to breakoff of a subduction slab.
The second cycle is synchronous with a Late Ordovician minor faulting event on Pearya terrane and volcanic units in the deep water basin between Pearya terrane and the carbonate platform. A major platform margin stepback, along with a positive epsilon-Nd shift are associated with the late Katian Irene Bay Formation. The event also introduced numerous organisms of Siberian affinity into northern Laurentia. The third cycle, starting in Ludlow time is related to the onset of deformation in the Boothia foldbelt and is not recorded as a deformational event on Pearya terrane.
The presence of aerially restricted intra-platform basins that are interpreted to be synchronous with, and caused by, tectonic events on Pearya terrane implies that it was close to its current location by Early Ordovician time.
Summary(Plain Language Summary, not published)
The geology of lower Paleozoic (around 600 to 360 million years ago) of the Canadian Arctic Islands is described. Seven main assemblages of rock are identified, each corresponding to a phase of the tectonic history of Arctic Canada. Seven types of hydrocarbon prospect are described based on their possible source rock, reservoir type, and timing of formation. Key risks for the preservation of hydrocarbons in the lower Paleozoic of the Canadian Arctic Islands are that many of the hydrocarbons formed and migrated before the traps developed; deep burial has destroyed porosity; and that the hydrocarbons were generated a very long time ago decreasing their chance of preservation.

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