THE 2013 ISACHSEN EXPEDITION TO AXEL HEIBERG ISLAND, NUNAVUT, CANADA: A FIELD REPORT

We report the results of field work carried out in July 2013 to investigate (1) the mineralogy and geochemistry of oxide-sulphide gossans and their reactive zones in permafrost and (2) the style of emplacement, age and composition of igneous rocks associated with the Early Cretaceous Isachsen Formation (Environmental Geoscience Program, Natural Resources Canada; and PhD thesis project, Carleton University). The study area is located near South Fiord, western Axel Heiberg Island (N 79.372, W 93.639) in Mesozoic strata of the Sverdrup Basin. The objectives of the field campaign included: (1) ground truthing of remote predictive geologic maps based on Landsat-7 Thematic Mapper, SPOT-5 and ASTER satellite imagery; (2) mapping and sampling of bedrock that hosts oxide-sulphide gossans; and (3) stream sediment sampling in the vicinity of each gossan occurrence. Several types of gossans were identified and classified according to the type of host rock and internal stratigraphy of soils overlying permafrost. Bulk and silt samples were collected from local streams for comparative geochemical studies of bedrock, gossans and stream sediments. Mafic sills and dykes sampled over a large area that included the South Fiord peninsula were investigated as potential feeders for basaltic lava flows in the Early Cretaceous Isachsen Formation. Spatiotemporal and compositional links with the Canadian High Arctic Large Igneous Province (HALIP) and related circum-Arctic magmatism are also being considered. In this contribution, we discuss the complex field relationships between the volcanic successions, associated intrusive rocks, sedimentary host rocks, evaporite diapirs, and base metal gossans. These appear to be typical of the Isachsen Formation in the study area, and in the Strand Fiord-Expedition Fiord region as a whole. We discuss the wide range of analytical studies in progress, including applied reflectance spectroscopy of gossan soils, petrography and mineralogy, bedrock and stream sediment geochemistry, and geochronology.