PALEOPRODUCTIVITY AND PALEOENVIRONMENTAL CONDITIONS FOLLOWING THE PERMIAN-TRIASSIC MASS EXTINCTION IN THE WESTERN CANADA SEDIMENTARY BASIN (PEACE RIVER BASIN) BRITISH COLUMBIA, CANADA

The recovery from the Permian-Triassic mass extinction was a complex event that exhibits a strong environmental influence. While many studies have examined macrofaunal trends, or have documented environmental conditions during the post-extinction interval, no significant amount of work has focused on the reestablishment of primary producers, a substantial step in the path to recovery. Lower Triassic sedimentary rocks from the Western Canada Sedimentary Basin (WCSB) provide an excellent means for reconstructing primary productivity in the wake of the Permian-Triassic mass extinction, and therefore determining temporal and spatial trends in the recovery of life at its most basic level. Primary productivity and paleoenvironmental conditions were reconstructed from a drill core (A8-7-85/18w6) that sampled the Dienerian-Smithian boundary interval (middle Early Triassic) within the Montney Formation from the Pedigree-Ring Border-Kahntah River area of northwestern Alberta and northeastern British Columbia. From this core a total of 75 samples were collected for analysis of major, minor, and trace element abundances using ICP-AES, in addition to %TOC and %TIC using the Loss on Ignition method. Results indicate that primary productivity was robust across the study interval as evidenced by enriched values of Ba and Ni when compared to average shale values, coupled with high TOC values ranging from 2-4% over the entire study interval. V and Mo enrichment factors as well as V/(V+Ni), were used to reconstruct paleoxygenation, which correlates to grain size, indicating that benthic oxygenation was controlled by relative changes in sea level. In general, the results of this study indicate sustained productivity in the WCSB, but with deeper, anoxic waters restricting biotic recovery to shallow, wave-agitated environments (i.e. the habitable zone). Future analyses of cores and outcrops from across the WCSB will further establish temporal and spatial trends in recovery and paleoenvironmental conditions following the Permian-Triassic extinction along the northwestern margin of Pangea.