Submarine-Cemented Pennsylvanian to Early Permian ‘Waulsortian’ and Palaeoaplysinid Reefs in the Canadian Arctic
In memory of Lloyd Pray, an external examiner for my Shark Bay doctoral thesis, and one of my ‘carbonate heros’ in the late 60s and 70s. Pennsylvanian (Late Carboniferous) ‘Waulsortian’ reefs and Pennsylvanian to Early Permian palaeoaplysinid reefs and mounds on Ellesmere Island in the Canadian Arctic Archipelago were examined by the author and associate Walter Nassichuk in the 1971 to 1974 field seasons, with some locations less than 1000 km from the north geographic pole. Palaeoaplysinid reefs also occur on Axel Heiberg Island, and collectively are similar to productive reefs in the Urals of Russia. The reef-builder Palaeoaplysina now is placed with the coralline red algae. ‘Waulsortian’ reefs on the Arctic islands are younger than classic Waulsortian buildups, but appear to be identical in composition and fabric. Many of the Arctic buildup occur in mid-shelf positions. The influence of internal waves/internal tides on reef localization must be considered. Both Arctic reef types are characterized by often spectacular submarine cements, including former isopachous Mg-calcite cements and botryoidal aragonite. Neptunian dikes/fractures in some Waulsortian reefs are lined by thick, multi-event submarine cements with microbial textures that are continuous with cements in reef cavities cut by the fractures. Very limited weathering under arid Arctic climatic conditions, and ‘glacial polishing’ of whole reef sections, provide extraordinary exposures in a logistically-difficult setting - Lloyd would have loved it!
AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017