| Principal Investigator: | Gosse, John C (3) |
| Licence Number: | 15228 |
| Organization: | Dalhousie University |
| Licensed Year(s): |
2013
|
| Issued: | Apr 12, 2013 |
| Project Team: | John Gosse, Natalia Rybczynski, Lea Braschi, Thomas Lakeman, Clayton Kennedy |
Objective(s): To collect fossils (i.e. peat, bone, wood, and other sedimentary proxies) for paleoenvironmental reconstructions; and, to document the age of the Beaufort Fm. at Ballast Brook, northwest Banks Island using a new approach based on the exposure of quartz sand grains to cosmic radiation: terrestrial cosmogenic nuclide (TCN) burial dating.
Project Description: The primary objectives are to i) collect fossils (i.e. peat, bone, wood, and other sedimentary proxies) for paleoenvironmental reconstructions and, ii) document the age of the Beaufort Formation (Fm) at Ballast Brook, northwest Banks Island using a new approach based on the exposure of quartz sand grains to cosmic radiation: terrestrial cosmogenic nuclide (TCN) burial dating. The cosmogenic nuclides, 26Al and 10Be, are produced at a fixed ratio in quartz at the Earth’s surface during exposure to cosmic-ray bombardment. Upon burial, 26Al and 10Be decay at different rates due to differing half-lives; thus the ratio 26Al/10Be can be used as a burial clock to estimate the age of buried sediments. Recently published TCN burial dating results from equivalent deposits on Ellesmere Island confirm a Pliocene age and provide a proof of concept for the approach. Sedimentary exposures of the Beaufort Fm. at Ballast Brook and at other, as yet unidentified, exposures on western Banks Island will be investigated in the field. Detailed sedimentological analyses of the exposures will permit the identification of correlative sediment layers and the reconstruction of specific depositional environments. Coarse quartz sand within previously and newly characterized sediment layers will be systematically sampled for TCN burial dating. This will involve the careful removal of surface debris (<0.5 m) from the exposures and the collection of 1-3 kg quartz sand samples, which will be transported to the Dalhousie Geochronology Centre, Department of Earth Sciences, Dalhousie University, where they will be processed for TCN burial dating using standard chemical procedures. Isotope measurements will take place at the Center for Accelerator Mass Spectrometry (CAMS), Lawrence Livermore National Laboratory, USA. As well, at each site, floral and faunal remains will be analyzed to establish former ecosystems and paleoclimates. Fossil collections will be managed at the Canadian Museum of Nature and analyses will be conducted at various laboratories: fossil wood and mollusks for climate reconstruction by A. Csank, Nipissing University; fossil leaves for climate and carbon dioxide reconstruction by D. Greenwood, Brandon University; vertebrate fossils for environmental reconstruction, evolution, and biogeography by N. Rybczynski, Canadian Museum of Nature. A research summary (including the research goals, preliminary results, and anticipated scientific significance) will be made available to the Sachs Harbour Hunters and Trappers Committee and Parks Canada in Fall 2013. The final results will be communicated following peer-review and publication in international scientific journals. The fieldwork for this study will be conducted from June 25, 2013 to August 31, 2013.
