Open File Report 5590 Bedrock geology, Strand Fiord–Expedition Fiord area, western Axel Heiberg Island, northern Nunavut (parts of NTS 59E, F, G, and H); Geological Survey of Canada Open File 5590, 1 CD-ROM. About the CD-ROM ---------------- This CD-ROM contains Open File 5590 in pdf V7.0.5 format. The pdf can be viewed using Adobe Acrobat V7.0.5 (included on the CD-ROM). It also contains a Microsoft® PowerPoint® Presentation that can be viewed using PowerPoint® Viewer 2003 (included on the CD-ROM). Axel Heiberg Island (Nunavut Territory) contains the thickest Mesozoic section in the Sverdrup Basin, and the ~370-km-long island is second only to Iran in the number and concentration of exposed evaporite diapirs. However, local geology and tectonic history have hardly been studied. The polar desert provides excellent exposure of 46 diapirs of Carboniferous evaporites and associated minibasins. Paleogene (Eurekan) sinusoidal and box-fold anticlines trend roughly north on a regular ~20-km wavelength, and probably detach on autochthonous Carboniferous Otto Fiord evaporites. In contrast, a 60-km-wide area, known as the wall-and-basin structure (WABS) province, has a characteristic wavelength of <10 km, irregular fold spacing, and bimodal fold trends. Crooked walls of diapiric anhydrite crop out in the cores of tight anticlines. Wider, open synclinal minibasins separate the diapir walls. We interpret the WABS province to detach on a shallow evaporite canopy. The only other known exposed evaporite canopy is in he Great Kavir of Iran. The WABS evaporite canopy comprises an allochthonous coalescence of evaporite diapirs that spread during the Hauterivian (mid-Cretaceous, ~130 Ma), close to the onset of sea floor spreading in Canada Basin and plume-related flood basalt volcanism associated with Alpha Ridge. Since then, the canopy has yielded second-generation diapirs, now exhumed and exposed by modest late Paleocene-Eocene shortening (Eurekan Orogeny). Local strata record minibasin evolution and diapirism since at least the Late Triassic. Diapir-flanking angular unconformities, involving proven reservoir sandstones, are present at four stratigraphic levels between the Jurassic and Paleocene. Most significant and widespread is the mid-Cretaceous event marking the time of canopy emplacement and spreading. Outcrops record the later fate of the canopy, including its subaerial exposure, onlap of diapiric evaporite, and off-diapir debris flows. Extensional tectonics evidently had a significant influence in the region from mid-Early Cretaceous (~125 Ma) to the mid-Late Cretaceous (~90 Ma) as indicated by diabase dyke swarms emplaced in several directions, extrusive basalt, and sills in most Mesozoic strata but especially common in the vicinity of some diapirs. A record of hyperactive fluid circulation includes fossil tufa deposits, migrated hydrocarbons, and metal sulphide deposits in diapir aureoles. Saline springs, recently-formed subaerial debris flows and geomorphically unstable diapir relief indicate that the evaporite canopy on western Axel Heiberg Island remains a geologically dynamic feature of the central Sverdrup Basin. Recommended citation -------------------- Harrison, J.C. and Jackson, M.P. 2008: Bedrock geology, Strand Fiord-Expedition Fiord area, western Axel Heiberg Island, northern Nunavut (parts of NTS 59E, F, G, and H); Geological Survey of Canada Open File 5590, 1 CD-ROM. If you are reading this with a Mac or Unix operating system the autostart will not work. The user will find of5590.pdf in the /pubs folder on this CD. Open files are products that have not gone through the GSC formal publication process. Contents: -------------------- abstract.txt (abstract of this publication) adobe.txt (Adobe Acrobat Reader attribution statement) citation.txt (how to refer to this CD) licence.txt (legal information) metadata.txt (standard metadata describing this CD publication) \apps\AdbeRdr705_enu_full.exe (Adobe Acrobat Reader) \pubs (publication contents in PDF V7.0.5 Format) Contact Information ------------------- Questions, suggestions, and comments regarding this CD-ROM should be addressed to: J.C. Harrison phone: (403) 292-7137 e-mail: charriso@nrcan.gc.ca fax: (403) 292-5377 mailing address: Geological Survey of Canada Calgary 3303 - 33 Street NW, Calgary, Alberta T2L 2A7 M.P. Jackson phone: (512) 475-9548 e-mail: martin.jackson@beg.utexas.edu fax: (512) 471-0140 mailing address: Bureau of Economic Geology The University of Texas at Austin, University Station, Box X, Austin, TX, U.S.A. 78713-8924