Reports: B2
47346-B2 Productivity and Environmental Conditions Following the Permian-Triassic Mass Extinction: Lower Triassic Rocks from the Western Canada Sedimentary Basin
ACS-PRF grant 47346-B2 supported the completion of the following tasks during 2008-2009:
a) Determination of trace element data related to Early Triassic paleoproductivity and paleoxygenation from stratigraphic sections across one outcrop locality in the Western Canada Sedimentary Basin (WCSB).
b) Submission of those results to the Fall 2009 meeting of the Geological Society of America with an undergraduate student collaborator as co-author.
c) Collection of additional outcrop samples from the central WCSB.
d) Processing of all previously collected samples for future ICP analysis.
During the summer of 2008, I travelled to the WCSB with two undergraduate students, Sean Keffer and Nathan Liodas, and collected samples from the Cadomin, AB section (Peace River Basin) at a higher resolution than previously collected for the pilot study. Upon return, Keffer spent the remainder of summer 2008 and winter 2009 processing samples that had been previously collected for future analysis on the ICP. Technical problems with the ICP during the summer of 2008 limited the amount of data that the PI was able to collect; these problems were overcome in January 2009. During the summer of 2009, Keffer was trained to run the ICP, and, along with Woods, collected trace element data from samples collected from the Opal Creek locality in the southern WCSB (Spray River Basin), which was deposited in a deep-water, offshore setting. Results from Opal Creek suggest that paleoproductivity collapsed at the Permian-Triassic boundary, but recovered quickly, and remained robust through the remainder of the Early Triassic recovery interval. Results also demonstrate that paleoxygenation levels were suboxic to anoxic from the Permian Triassic boundary through the Griesbachian, and shifted to oxic conditions for the remainder of the Early Triassic. This data differs from the pilot data from the Cadomin locality in the Peace River Basin, which primarily sampled lower shoreface facies, and documents variations in paleoproductivity that correlate to shifts in paleoxygenation across much of the post-extinction interval. These results may be the result of the more shoreward Cadomin locality being closer to the locus of upwelling, or may be due to local paleobathymetric variations. Continued trace element analysis of samples collected elsewhere in both sub-basins, as well as from the northernmost Liard Basin, should shed light on the reasons for this dichotomy. Keffer will collect trace element data during the Fall of 2009 from a drill core collected from the Liard Basin, the northernmost sub-basin of the WCSB. This data will be used in Keffer's undergraduate thesis, and will provide a means to examine temporal and spatial changes in paleoproductivity and paleoxygenation across a wide latitudinal swath of western North America during the Early Triassic. Liodas will collect total organic carbon (TOC) and total carbonate carbon (TCC) data from samples from the same drill core as Keffer for his undergraduate thesis, which will provide a further means to examine Early Triassic paleoproductivity, while a third undergraduate student, Ryan Wakefield, will collect TOC and TCC data from samples from the Opal Creek locality. Liodas plans to complete his undergraduate thesis during the Fall 2009 semester, while Keffer and Wakefield plan to finish their theses during Summer 2010. All three students will present the results of their research at the 2010 meeting of the Cordilleran section of the Geological Society of America in Anaheim, CA. This research has positively impacted the PI by allowing the PI to expand his research interests beyond his previous experience (primarily the sedimentology and petrography of unusual Lower Triassic carbonates) and by fostering collaborative relationships with several international colleagues (Tyler Beatty, J.-P. Zonneveld, Charles Henderson). The undergraduate students involved with the research have learned technical skills that they would not likely have obtained otherwise, and are collecting and interpreting data related to a large, multidisciplinary problem. In addition, the students will also have the opportunity to interact with other researchers and potential graduate advisors when they present their data at the 2010 Cordilleran meeting of the GSA.
