ARCTIC Maps of the Arctic Basin Sea Floor
ABSTRACT. The general scarcity of geophysical data in the Arctic Ocean Basin and the lack of knowledge about the evolution of the Amerasia Basin and of the nature and origin of the Alpha Ridge led, in 1983, to the undertaking of a multidisciplinary polar expedition, code-named CESAR 83 for Canadian...
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| Format: | Text |
| Language: | English |
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1986
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.528.8331 http://pubs.aina.ucalgary.ca/arctic/Arctic40-1-1.pdf |
| Summary: | ABSTRACT. The general scarcity of geophysical data in the Arctic Ocean Basin and the lack of knowledge about the evolution of the Amerasia Basin and of the nature and origin of the Alpha Ridge led, in 1983, to the undertaking of a multidisciplinary polar expedition, code-named CESAR 83 for Canadian Expedition to Study the Alpha Ridge. The expedition was supported by the Canadian Armed Forces, first by parachuting 18 airborne engineers onto the CESAR site to build a 1.6 km long airstrip on the pack ice, and then by deploying and two months later evacuating the expedition by military Hercules aircraft. The search for a suitable site on the sea ice was facilitated by a preceding side-looking airborne radar (SLAR) reconnaissance survey of the area. One of the major CESAR accomplishments was a regional bathymetric and gravity survey over the Ellesmere Island continental shelf and eastern part of the Alpha Ridge. Using the CESAR data as well as all publicly available data collected over the past 35 years, 1 0 0 m contour interval bathymetric maps and 5 mGal contour interval gravity free-air anomaly maps were compiled. These extend from the Ellesmere Island coast to the 116’W meridian. The sea floor maps depict the Alpha Ridge as a very broad mountain complex of rugged topography with ridges and valleys trending parallel to the ridge axis. A prominent east-southeast trending valley centered along 86”N latitude between 110 ” and 125”W longitude was named Cesar Trough and the adjoining ridges Cesar North Ridge and Cesar South Ridge. The Alpha Ridge is separated from the Ellesmere Island continental shelf by a trough 1800-2000 m deep. Over the ridge the free-air anomalies mirror the bathymetry. Elliptically shaped positive anomalies centered over the continental shelf break suggest that the continental margin adjacent to the Alpha Ridge has the typical At!antic-type structure characteristic of the rest of the North American polar margin. Preliminary interpretation of the gravity field indicates that the Alpha Ridge crust ... |
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