Michael Hofmann, University of Montana EAR-1338441 This award is co-funded by NSF's Section of International Science and Engineering. PI will travel to and conduct field research in the Yunnan Province, China, to document and sample a newly discovered exposure of the Maotianshan Shale interval in the Jianshan quarry. This project is urgent, because the exposure will be removed in April 2013 when mining resumes. This laterally continuous outcrop exposes the entire Maotianshan Shale interval over several hundred meters, making it a unique study site to address many of the sedimentologic and stratigraphic uncertainties associated with the Maotianshan Shale deposition and fossil preservation. In addition to salvaging the fossil fauna, PIs plan to systematically describe the overall stratigraphy of the Maotinashan Shale and to document the detailed rock fabrics and sedimentology. In particular they will focus on the fossil bearing layers in order to test the hypothesis that mesopycnal flows in a stratified marginal marine basin contributed to the exceptional preservation of the Changjiang Fauna. Working with Chinese colleagues and their students, the university of Montana graduate student will experience synergistic, interdisciplinary research and international collaboration in geology.
The Early Cambrian Maotianshan Shale near Kunming, China, contains some of the world’s best preserved fossils, documenting the onset of many living animal groups during the Cambrian Explosion. This fauna has been recognized by the UNESCO as a world heritage site and has been regarded as one of the most important Lagerstätten deposits since its discovery in the last century. Although earlier studies interpreted the depositional environment of the Maotianshan Shale, to date there is no satisfying explanation of the sedimentary processes that governed the deposition of these rocks and that might have contributed to the exceptional and unique preservation of the Changjiang Fauna. NSF-RAPID funding was granted solely to help document the sedimentology and startigraphy from an exceptionally well exposed outcrop of the Maotianshan Shale in the Jianshan Mine, Yunnan province, that has since been removed by mining operations. This grant did not include any funding for subsequent analysis. The project progressed as proposed and in a collaborative effort with our Chinese partners we recorded a series of stratigraphic sections on a centimeter scale and, in all, sampled 96 rock samples from the Jianshan Mine. These samples were shipped back to the United States and are now serving as the only rock record of this important outcrop of the Maotianshan Shale. Part of these samples have since been analyzed for mineralogy and petrography. In addition to the proposed data set we were able to acquire rock samples for detrital Zircon extraction and dating. Processing and data analysis were performed by our Chinese collaborators and these samples provide the first direct chronostratigraphic dates for the Maotianshan Shale in the area. The project produced three co-authored publications to date. In the first paper we described the facies heterogeneity and sediment dispersal patterns of the Maotianshan Shale. This work was presented at the Geological Society of America National meeting in Denver in October 2013. A follow up peer reviewed journal publication is being prepared and will be submitted in the next few weeks. The third paper (submission in early 2014) focuses on the chronology of the Maotianshan Shale based on the results from detrital Zircon dating. In addition, this grant helped to establish international relationship between the PI and Chinese scientists, and part of the funding was used to support a PhD student at the University of Montana.
