A radiocarbon-dated gelifluction lobe in the Nachvak Fiord area,northern Labrador,Canada

Radiocarbon dates obtained on organic materials overridden by a gelifluction lobe allow some estimate of past gelifluction rates for a site near sea level in northern Labrador. The calculated mean gelifluction rate for the last 400 years is in the order of 8 mm yr^?1, somewhat higher than the average gelifluction rate described from other locations in the Canadian Arctic. The lobe contains two lithostratigraphic units: an inner diamicton, probably representing a buried gelifluction lobe, overlain by a silt/clay unit which may have been emplaced abruptly as a solifluction sheet. Mean creep rates for these units were in the order of 5 mm yr^?1 and 15 mm yr^?1 respectively. The area is presently subsiding, and transgressive beach material overlies terrestrial organics which are approximately 300 years old.