Abstract

The sedimentary succession of the Sverdrup Basin, Canadian Arctic, records an important Permian climatic cooling trend. Highly diversified, tropical associations dominated by calcareous alga and foraminifer (chloroforam) prevailed in the Asselian and Sakmarian, whereas poorly diversified, temperate associations, dominated by bryozoan, echinoderm, brachiopod, and sponge (bryonoderm) characterized the post-Sakmarian interval. Carbonates that formed in the tropical environment differ greatly from carbonates that accumulated in the temperate environment. Permian temperate carbonates also differ from their tropical counterparts by the paucity or absence of associated reefs, ooids, peloids, and submarine cements. Temperature is responsible for differences between tropical (warm-water) and temperate (cool-water) carbonates, so temperate-like carbonates also occur in deeper water low latitude environments.

Five cores showing differences between tropical (chloroforam) and temperate (bryonoderm) Permian carbonates of the Sverdrup Basin are displayed. These cores were recovered from four wells drilled in the western Arctic (Marryatt K-71, Chads Creek B-64, Sherard Bay F-34, and Buckingham O-68).