Collect multichannel seismic, sonobuoy, and single-beam echo sounder data as part of identifying the boundary of the U.S. extended continental shelf in the Amerasian (Canada) basin of the Arctic Ocean.
Location
Canada Basin, Amerasian Basin, United States, Canada, North America, Arctic Ocean;
Summary
This cruise was a joint marine expedition between the Geological Survey of Canada and the United States Geological Survey, undertaken in the Canada Basin from the Canadian polar margin to the Northwind Ridge of the Chukchi Borderland. In this region ice conditions create conditions difficult for collecting underway geophysical information and a two-ship survey was required. The Canadian Coast Guard Ship LOUIS S. ST. LAURENT (LSSL) collected data in single ship mode during the period of August 21 to September 9, 2008. For the period of September 10 to 27 the United States Coast Guard Cutter HEALY accompanied the LSSL and contributed multibeam bathymetric data and high-resolution chirp sub-bottom profiler. The HEALY broke ice for the LSSL during seismic operations and the LSSL broke ice ahead of HEALY when multibeam was the important data set. The information was acquired in order to meet the requirements of Article 76 of the United Nations Convention on the Law of the Sea (UNCLOS) so that Canada can determine the boundaries of its extended continental shelf and for the United States to make a similar assessment. Data collected aboard LSSL were: 2817.1 km - multichannel seismic data; noise tests and signature tests; 85,664 - total shots fired; 12 - number of seismic lines; 4849 km - echo sounder (12 kHz) profiles; 181 - spot soundings from helicopter; 39 - total sonobuoys deployed; 4 - failed sonobuoys; 67 XCTDs - expendable CTDs for water column temperature and salinity (and velocity); 3 instances of shutting down the airguns for marine mammals (1 polar bear sighting, 2 seal sightings).
Info derived
Sediment thickness and geological history;
Comments
*** Availability of Seismic Data - Until the date that Canada submits its extended continental shelf limits to the Commission on the Limits of the Continental Shelf (by December 6, 2013), the seismic data will not be released to other researchers except by mutual consent of both GSC and USGS. After that date and up to December 6, 2016, if the data have not been publicly released, researchers interested in the data for scientific purposes can submit a request to Natural Resources Canada (Geological Survey of Canada, (GSC) to obtain copies of the data. Upon consultation with USGS about use of the data, GSC should not unreasonably withhold permission to use the data as long as it is for scientific purposes and involves collaboration with GSC or USGS in their use and publication of results. The data should be fully publicly released with no restrictions on its use after December 6, 2016. Seismic data include seismic reflection and refraction data collected using equipment from LOUIS S. ST. LAURENT. Until public release, the official copy of these data are held at NRCan, Earth Sciences Sector. After public release, the data will be available through NRCan, Earth Sciences Sector. *** Availability of Singlebeam Echo Sounder Data - Data outside of the Canadian 200-nm limit are available through the Department of Fisheries and Oceans. Data inside the 200-nm limit are considered proprietary under release policy of the seismic data (see above). Until public release, the official copy of these data will be held at DFO, Canadian Hydrographic Service (CHS). After public release, the data will be available through CHS. *** Availability of Other Data - Other data collected during the LSSL cruise, such as navigation, gravity, velocimeter profiles, CTD casts for water velocity, and ice imagery are considered supporting data that are included in cruise reports and other documentation as public information. They are not necessarily formally released but will be supplied upon request to either GSC or CHS.
Project = Interagency Task Force Cooperative, Interagency Task Force Cooperative
Seismic noise and signature tests: Noise tests were done using passive recording with the geometrix multichannel streamer. Signature tests were done using the airgun array plus calibration hydrophone.
