A refraction seismic image of the sediments in Kennedy Channel, northern Nares Strait

Thomas Funck, Sonya A. Dehler, H. Ruth Jackson, Matthew H. Salisbury, Ian D. Reid

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

Abstrakt

A refraction / wide-angle reflection seismic study was carried out in the 35-km wide Kennedy Channel in northern Nares Strait between Greenland and Ellesmere Island, Canada. The objective was to study the uppermost subsurface structure in the channel, where a hypothesized strike-slip fault (Wegener Fault) could mark the plate boundary between Greenland and North
America. Three land-stations (one on either side of the channel and a third one on Hans Island) recorded densely spaced airgun shots along three lines.
However, ice conditions limited the observations in the western part of the channel. With the given shot–receiver offsets of <44 km, the velocity structure
of the uppermost sediment layer could be determined by forward and inverse modeling. This layer has P-wave velocities of 5.8 to 5.9 km s-1 in the west and
6.1 to 6.2 km s-1 in the east. The Poisson’s ratios vary between 0.28 and 0.31 in the west, and between 0.31 and 0.32 in the east. The lateral velocity change
occurs close to Hans Island. From the obtained velocities it is inferred that the sediment layer consists of carbonates. P-wave velocity measurements on a
limestone sample from Greenland (5.9 to 6.1 km s-1) are compatible with the high velocities found in the channel. In eastern Kennedy Channel, the base of
the carbonate layer shallows towards the north, from 4.5 km to 3.5 km over a lateral distance of c. 10 km. West of Hans Island, the base of the carbonate layer is not constrained. Absence of sharp offsets at the base of the carbonates make it not very probable that a major strike-slip fault runs through the eastern part of Kennedy Channel. This is consistent with observations from bathymetric and reflection seismic data, which show a steep fault just west of Hans Island.
OriginalsprogEngelsk
Sider (fra-til)41-50
Antal sider10
TidsskriftPolarforschung
Vol/bind74
Udgave nummer1-3
DOI
StatusUdgivet - 2006
Udgivet eksterntJa

Programområde

  • Programområde 3: Energiressourcer

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