The Sverdrup Basin
in Nunavut, Arctic Canada, contains the world's second-largest concentration
of emergent salt diapirs on Earth. More than 40 emergent diapirs are known
on Axel Heiberg Island in the center of the Sverdrup Basin. As part of
the Applied Geodynamics Laboratory (AGL) research program, Martin Jackson
spent 3 weeks during June and July on Axel Heiberg Island and adjoining
northern Ellesmere Island, collaborating with Dr. Christopher Harrison
of the Geological Survey of Canada (Calgary). For 2 weeks, they mapped
three diapirs using tent camps that were periodically moved and resupplied
by helicopter. They also spent a week at Canada's Polar Continental Shelf
Project base at the Eureka weather station on Ellesmere Island, from where
they went on day trips to other diapirs and key outcrops by helicopter.
Their work was part of a larger Arctic research program and workshop organized
and led by Dr. Benoit Beauchamp of the Geological Survey of Canada (GSC).
This program required 18 months of logistical preparation by the GSC,
including laying in fuel caches for the helicopters the previous summer.
In midsummer, even at a latitude of 80°, tundra around the diapirs
is largely free of snowfortunately for geologistsalthough
the island contains a large permanent ice cap, innumerable glaciers, and
evaporite diapirs consist mostly of anhydrite, underlain by halite and
weathering to a gypsum skin. The diapirs were squeezed by the early Tertiary
Eurekan orogeny. Separating the diapirs are minibasins, which are also
excellently exposed at the surface. Like the diapirs, they offer scientists
an opportunity to investigate firsthand a geologic system similar to that
in the Gulf of Mexico, which is either deeply buried or in deep water
and thus inaccessible to direct observation.
Research results will
first be presented in November at AGL's annual review meeting for sponsoring