Tracing sand-types across the Sverdrup Basin

Within the Late Paleozoic-Cretaceous Sverdrup Basin and the overlying Paleogene strata there are thick, laterally extensive, commonly quartz-rich, sandstone-dominated formations. These sandstones yield provenance data which may, on a circum-Arctic scale, cause us to question current plate and palaeogeographic reconstructions, and locally, help to trace and predict the occurrence of hydrocarbon reservoirs.

The study involved 4 field seasons along the northern and southeastern margins of the Sverdrup Basin on Ellesmere and Axel Heiberg islands. Our approach involves collection of field data by multidisciplinary teams and a comprehensive analytical programme. An age framework is provided by integrated biostratigraphy (macropalaeontology, palynology and micropaleontology). Sediment provenance and transportation information is provided by field observations, petrography, heavy mineral analysis, mineral geochemistry, detrital zircon dating, and palynology (reworked fossil). Uplift and burial histories are provided by vitrinite reflectance and apatite fission track analysis.

We will use an example from the southeastern Sverdrup Basin, Slidre Fiord, Ellesmere Island, to illustrate the changes in sediment provenance observed, and then begin to trace these changes to other parts of the basin. At Slidre Fiord we identify at least 4 sand-types and can place time constraints upon the provenance changes:

• Triassic (Norian and older) and mid Jurassic sandstones have common provenance signatures; they are sublitharenites and subarkoses with abundant apatite and Permo-Triassic detrital zircons
• At the Triassic-Jurassic boundary there is a pulse of mature sandstone, lacking in apatite and Permo-Triassic detrital zircons
• During the mid Jurassic the metamorphic grade of the sediment source area increased, suggesting either an unroofing history, different or possibly deeper source
• Early Cretaceous mature sandstones have a different signature to the underlying units, containing abundant Proterozoic-Archean detrital zircons
• Late Cretaceous-Paleogene sandstones contain kyanite (high-pressure metamorphism) and volcanic debris

Many of the provenance signatures we see on the southeastern margin also occur on the opposing, northern margin of the basin. The data from this on-going study provide a framework on which we can base models of sediment provenance and transport, therefore constraining palaeogeographic reconstructions.