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Project Progress

During the past year our group continued to investigate mass extinctions, their effects, and their aftermath. We continued stable isotopic examination of material from Triassic/Jurassic and Permian/Triassic sites. PhD Candidate Kenneth Williford started work on organic biomarkers extracted from already sampled rocks from Canada and Nevada, and also spent four weeks in New Zealand collecting a new suite of samples from Triassic/Jurassic strata previously studied by PI Ward and Williford in 2003. Our new work demonstrated the presence of a large positive carbon isotope anomaly from both Nevadan and Queen Charlotte Island T/J sites, thus for the first time demonstrating a similarity in isotopic composition between these T/J sites and previously studied Permian/Triassic sites.

The biomarker work now suggests that the Triassic mass extinction, similar to the Permian mass extinction, was accompanied by a large scale bloom of photosynthetic sulfur bacteria indicating that deleterious conditions of low oxygen and a high flux of hydrogen sulfide may have occurred at the end of the Triassic.

Also in this year we received samples from the Impact Focus Group sampling trip to Meishan, China, and we have begun analyses of these. We also received results from both iridium analyses (UCLA member Frank Kyte) and UW member Ken Farley (see his separate project description) on 3He results. Neither showed any evidence for impact at the end of the Triassic.