Evolution of the Eastern Sverdrup Basin: Insights from New Field Studies and Sediment Provenance Analyses
Helen R. Smyth1, Simon R. Kelly1, Andrew Morton2, Stephen Rippington1, Robert Scott1, Jenny E. Omma1, Bill Braham1, John E. Marshall3, Victoria Pease4, and Andrew Carter5
1CASP, University of Cambridge, Cambridge, United Kingdom.
2HM Research Associates, Balsall Common, United Kingdom.
3School of Ocean and Earth Science, University of Southampton, Southampton, United Kingdom.
4Department of Geology and Geochemistry, University of Stockholm, Stockholm, Sweden.
5School of Earth Sciences, University College London, London, United Kingdom.
The Late Paleozoic-Mesozoic strata of the Sverdrup Basin and the overlying Cenozoic deposits have been examined during three field seasons on Ellesmere and Axel Heiberg islands, Canadian Arctic. Our field studies are supported by integrated biostratigraphic analysis, a variety of sediment provenance analyses (including; petrography, heavy mineral provenance, mineral geochemistry and U-Pb dating of zircons), and hydrocarbon source rock and uplift analyses. The results from this integrated study will help to constrain not only the tectonic evolution of the Sverdrup Basin and its Cenozoic exhumation, but also define the character of the sediment sources that were eroded to generate its fill.
The following observations can be made:
1. Sedimentary reworking and recycling is noted throughout the section, based on the evidence of detrital minerals and palynomorph assemblage. In some intervals Devonian palynomorphs are prevalent. The age of reworked material becomes progressively younger upsection.
2. Quartz-rich sandstones are a common feature of the basin They are often difficult to distinguish in the field, but they have distinct petrographic, heavy mineral, and detrital zircon age signatures.
3. Mineral geochemistry indicates that during the Jurassic there was a transition from low-grade to high-grade metamorphic sedimentary sources.
4. There is a contribution of fresh acidic volcanic material to the Late Cretaceous-Early Cenozoic section, including bentonites and minerals characteristic of a volcanic source (e.g. prismatic apatite, bipyramidal quartz and smetite). The source for the material remains uncertain, but contemporaneous sources include the Hansen Point Volcanics of northern Ellesmere Island. As the Canadian Arctic is bounded to the north and southeast by ocean basins, it remains unclear what type of tectonic regime led to the eruption of such acidic magma.
The implications of this study are not confined to the Sverdrup Basin. During the Palaeozoic, prior to the opening of the Arctic Ocean and the North Atlantic, the Canadian Arctic, Greenland, Svalbard and the Barents Shelf formed part of the same, east-west orientated shelf, defining the northern margin of Pangaea. Consequently, Sverdrup Basin sediments may serve as an analogue for subsurface deposits elsewhere on this Paleozoic shelf. Furthermore, this new data may help to constrain the timing of Amerasia Basin opening, and Late Cretaceous to Paleogene plate reconstructions.
AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia