| Title | Evidence for protracted High Arctic large igneous province magmatism in the central Sverdrup Basin from stratigraphy, geochronology, and paleodepths of saucer-shaped sills |
| Author | Evenchick, C A; Davis, W J; Bédard, J H; Hayward, N; Friedman, R M |
| Source | Geological Society of America Bulletin 2015 p. 1-25, https://doi.org/10.1130/B31190.1 |
| Year | 2015 |
| Alt Series | Earth Sciences Sector, Contribution Series 20140193 |
| Publisher | Geological Society of America |
| Document | serial |
| Lang. | English |
| Media | on-line; digital |
| File format | pdf |
| Province | Nunavut |
| NTS | 69D/13; 69E/04; 69F; 69G/02; 69G/03; 69G/04; 69G/05; 79E/09; 79E/16; 79H/01; 79H/02; 79H/07; 79H/08 |
| Area | Sverdrup Basin; Ellef Ringnes Island |
| Lat/Long WENS | -106.0000 -99.0000 79.5000 77.7500 |
| Subjects | geochronology; stratigraphy; stratigraphic analyses; systematic stratigraphy; sedimentary rocks; magmatism; igneous rocks; uranium lead dates; uranium lead dating; magmatic rocks; Sverdrup Basin;
Beaufort Formation; Eureka Sound Group; Kanguk Formation; Hassel Formation; Christopher Formation; Isachsen Formation; Deer Bay Formation; Ringnes Formation; McConnell Formation; Jameson Bay Formation; King Christian Formation; Cenozoic; Tertiary;
Mesozoic; Cretaceous; Jurassic; Paleozoic |
| Illustrations | location maps; photographs; stratigraphic columns; plots; tables; Concordia diagrams |
| |
| Program | Western Arctic, High Arctic LIP, GEM2: Geo-mapping for Energy and Minerals |
| Abstract | Field evidence, map compilation, geochemistry, geochronology, and potential field data document six intervals of Cretaceous magmatism in the central Sverdrup Basin. These are: (1) Hauterivian (ca. 130
Ma) volcaniclastic deposition in the lower Isachsen Formation; (2) 126.6 ± 1.2 Ma (U-Pb zircon) gabbroic intrusion; (3) 120.8 ± 0.8 Ma (U-Pb baddeleyite) diabasic intrusion; (4) 105.40 ± 0.22 Ma (U-Pb detrital zircon) pyroclastic deposition at the
top of the Invincible Point Member, Christopher Formation; (5) upper Albian (ca. 103 Ma) pillow and hydroclastic breccia in the upper Christopher Formation; and (6) uppermost Albian (ca. 101 Ma) volcanic breccia and scoria in the Hassel Formation.
Whole-rock geochemical data show that these magmatic rocks are similar to previously documented High Arctic large igneous province tholeiitic basalts, but analyses of fresh glass in tuffs reveal evolved ferroandesite to dacite compositions not
recorded in whole-rock data. Approximate ages of saucer-shaped sills inferred from the relationship of sill width to depth of emplacement suggest at least three intervals of sill emplacement between 130 and 120 Ma. The new data show that volcanism in
the Sverdrup Basin was of greater spatial extent, and that magmatism occurred more frequently, than was previously recognized. Comparison of the new central Sverdrup Basin data and interpretations with other data sets from the Sverdrup Basin,
Svalbard, and Franz Josef Land suggests that High Arctic large igneous province magmatism occurred over a more extended period of time in the central Sverdrup Basin than in other regions. |
| Summary | (Plain Language Summary, not published)
The evolution of the Arctic Ocean between the Canadian Arctic Islands, Alaska, Arctic Norway, and Siberia is uncertain because conventional methods of
determining the timing and geometry of new ocean basin formation cannot be applied with confidence. The creation of a new ocean basin is accompanied by the formation of igneous rock, therefore an understanding of the types and ages of igneous rocks
in the Canadian Arctic may help our understanding of the evolution of the Arctic Ocean. In this paper we document and interpret newly recognized igneous rock occurrences on Ellef Ringnes Is., Nunavut, and compare them to other igneous rocks in the
Arctic. They include volcanic rocks that resulted from extrusion of magma at the earth¿s surface, and intrusive rock that resulted from solidification of magma below the surface. We document 6 periods of igneous activity between 130 and 101 million
years ago. The ages include periods of igneous activity not recognized in other regions of the Arctic. |
| GEOSCAN ID | 295149 |
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