Paleomagnetism of Canadian Arctic permafrost; Quaternary magnetostratigraphy of the Mackenzie Delta

A total of 357 samples taken from two long cores (Taglu, Kumak) drilled in the Mackenzie River delta have been investigated paleomagnetically. Remanence and susceptibility were measured in the field while the samples were still frozen. Profiles of susceptibility (5772 measurements) permit lateral correlation and imply that the average accumulation rate at Taglu was ~50% greater than that at Kumak, which lies 15 km to the southwest. Polarity reversals were found in both cores. The Matuyama–Brunhes boundary occurs at depths of 152 and 111 m at Taglu and Kumak, respectively; corresponding depths for the Gauss – Matuyama boundary are 356 and 243 m. In addition to the major chrons, we also find evidence of the Olduvai and Jaramillo subchrons. The chronology based on these data suggests that a major change in sedimentation history occurred about 1.5 Ma ago. This feasibility study thus suggests that paleomagnetism has chronological potential in permafrost environments that are currently important in frontier hydrocarbon exploration and as natural gas hydrate reservoirs.