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TitreExpedition report for the Alpha Ridge test of appurtenance (ARTA) 2008
AuteurJackson, H R (éd.); Potter, D P (éd.)
SourceCommission géologique du Canada, Dossier public 6842, 2016, 123 pages, (Accès ouvert)
ÉditeurRessources naturelles Canada
Documentdossier public
Mediaen ligne; numérique
ProvinceRégion extracotière du nord
Lat/Long OENS-105.0000 -87.0000 84.5000 81.3333
Sujetslevés géophysiques; levés sismiques; levés de refraction sismiques; levés de reflexion sismiques; gravité; levés sismiques marins; géologie marine; géophysique
Illustrationslocation maps; tables; photographs; screen captures; profiles
ProgrammePréparation d'une soumission pour un plateau continental élargi dans les océans Atlantique et Arctique sur le droit de la mer (UNCLOS), Délimitation du plateau continental du Canada en vertu de la Convention des Nations Unies sur le droit de la mer (UNCLOS)
Diffusé2016 09 12
Résumé(Sommaire disponible en anglais seulement)
Canada signed the United Nations Convention on the Law of the Sea in 2003. Article 76 of the treaty provides the rules for extending a country's territory beyond the 200 NM limit. The purpose of the Alpha Ridge Test of Appurtenance (ARTA) project was to determine if the Alpha Ridge is a natural prolongation of the continental margin north of Ellesmere and Axel Heiberg islands and to determine the position of foot of the bathymetric slope. Wide angle reflection/refraction (WAR) data and bathymetry were collected to meet the conditions of the treaty.
Data collection took place between March 22 and April 30, 2008. Eureka, Nunavut was the land base to which the fuel, explosives, camp, and scientific equipment were shipped. Because Eureka is 220 km from the coast, it was necessary to establish two camps on the sea ice in order for the aircraft to safely fly the distances required for data collection.
Three wide angle reflection/refraction profiles were run as planned (Fig. 1.1).The principle wide angle reflection /refraction profile was 350 km long, running north from the coast, and was shot as two line segments. In addition, a cross line of 174 km was established, and an initial test line was run near the mouth of Nansen Sound. For the Test Line, three shots were fired to 30 instruments that, due to the lack of ice motion, produced excellent data. These data provide the sedimentary and upper crustal arrivals useful in tracing the onshore velocities offshore. On the next portion of the line (the Inner Line), 11 shots were detonated to 115 instruments that also saved high signal-to-noise arrivals on 114 of 115 recorders. Following this, on the Outer Line 11 shots were fired to 115 recorders, all retaining data. On the Cross Line, 9 shots were fired to 114 recorders and all saved good quality data. In regions which saw appreciable ice movement, specifically on the Cross and Outer lines, the signal-to-noise ratio is reduced. In total, 3,635 seismic traces recorded. Arrivals from sedimentary layers all the way down through the crust to the Moho were observed. In addition, a CP140 Aurora air-dropped 15 geobuoys (seismic receivers) at the north end of the wide angle reflection/refraction line into which a total of 6 shots were fired. Three broadband seismometers were placed near the mouth of Nansen Sound to record the shots throughout the experiment as well.
A single channel reflection profile was also collected in the region about 23 km to the west (shown in Fig. 1.1) of the intersection Outer and Cross lines. At the site, a 10 in3 airgun was fired for 14 days, which clearly revealed up to 1.0 second of sediment. Basement surface and sub-basement internal reflections were also observed. During the shooting period, the ice drifted nearly 27 km.
The hydrographic program consisted of measuring the bathymetry at every recorder position and gravity at every second position along the WAR profiles.