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TitleLate Paleozoic to Triassic arc magmatism north of the Sverdrup Basin in the Canadian Arctic: evidence from detrital zircon U-Pb geochronology
AuthorAlonso-Torres, D; Beauchamp, B; Guest, B; Hadlari, T; Matthews, W
SourceLithosphere vol. 10, no. 3, 2018 p. 426-445, (Open Access)
Alt SeriesNatural Resources Canada, Contribution Series 20170373
PublisherGeological Society of America
Mediapaper; on-line; digital
File formatpdf; html
ProvinceNunavut; Northwest Territories
NTS29; 39; 49; 59; 69; 79; 89; 120; 340; 560
AreaCanadian Arctic Archipelago; Ellesmere Island; Axel Heiberg Island
Lat/Long WENS-120.0000 -60.0000 85.0000 76.0000
Subjectstectonics; geochronology; tectonic history; magmatism; magmatic arcs; subduction; volcanism; plate margins; rifting; basin evolution; depositional history; clastics; provenance; paleogeography; radiometric dating; uranium lead dating; zircon dates; bedrock geology; lithology; sedimentary rocks; carbonates; cherts; mudstones; conglomerates; sandstones; shales; evaporites; wells; Sverdrup Basin; Appalachian Orogeny; Caledonian Orogeny; Taconic Orogeny; Scandian Orogeny; Laurentia; Pacific Margin; Brock C-50 Well; Isachsen J-37 Well; Ellesmerian Orogen; Franklinian Basin; Chukchi Shelf; backarcs; retroarcs; basin inversion; convergent margins; siliciclastics; Phanerozoic; Mesozoic; Triassic; Paleozoic; Permian; Carboniferous; Pennsylvanian; Devonian; Silurian; Precambrian; Proterozoic
Illustrationslocation maps; geoscientific sketch maps; stratigraphic columns; tables; photographs; plots; histograms; schematic models; schematic cross-sections
ProgramWestern Arctic, Pearya Terrane, North Ellesmere, GEM2: Geo-mapping for Energy and Minerals
Released2018 03 23
AbstractPaleozoic and Mesozoic tectonic reconstructions of the Arctic regions have been a subject of debate in recent years. The Permian emergence of a landmass north of the Sverdrup Basin in the Canadian Arctic led to the shedding of northerly derived detritus, an event that followed volcanism and basin inversion pulses that began in the late Pennsylvanian. However, the mechanisms for these events and the Paleozoic to Mesozoic paleogeography of this region remain controversial.
New detrital zircon U-Pb geochronology results from Permian to Lower Triassic strata from northern Axel Heiberg and Ellesmere islands constrain the magmatic events within this northern landmass and its implications for the tectonic regime of the Sverdrup Basin and adjacent domains. Permian to lowermost Triassic strata along the northern margin of the Sverdrup Basin contain zircons derived from Silurian to Devonian rocks (420-350 Ma), Timanian-aged basement (700-500 Ma), and a Permian syndepositional source (300-250 Ma). Coeval strata in the southern margin are dominated by zircons formed during the Taconic, Scandian, and post-Scandian phases of the Appalachian and Caledonian orogenies, respectively (480-400 Ma).
The detrital zircon signatures of the analyzed strata on the northern margin of the Sverdrup Basin record continuous magmatism within the northern landmass from latest Carboniferous (ca. 300 Ma) to at least earliest Triassic (ca. 250 Ma) time. These results are indicative of ongoing subduction and development of a magmatic arc off the northern margin of Laurentia, with the Sverdrup Basin potentially located in the backarc region of a proto-Pacific convergent margin involving parts of Arctic Alaska, Chukotka, and the Chukchi Shelf. The hypothesized onset of subduction in latest Carboniferous time and closure of this backarc basin in the latest Permian to earliest Triassic provides an explanation for the shift in stress regimes in the Sverdrup Basin that led to basin inversion and volcanism episodes. Therefore, the data presented here supports a backarc to retroarc setting for the Sverdrup Basin and the possibility of a convergent margin regime for the northern edge of Laurentia during the late Paleozoic to Triassic, contrasting with the generally accepted rift and passive margin settings.
Summary(Plain Language Summary, not published)
This paper presents data that are interpreted to propose changing fundamental models for the origin of the Sverdrup Basin. Older models explain the basin setting as passive extension, whereas this paper suggests it was a back-arc setting, much the same as southeast mainland China adjacent to the Japan Sea.