Analysis of the multicomponent magnetization of the Little Dal Group, Mackenzie Mountains, Northwest Territories, Canada

Abstract

A paleomagnetic study on 14 red limestone sites of the Helikian Little Dal Group, ‘basinal sequence’ (Mackenzie Mountains, Northwest Territories, Canada) resolved five magnetizations using thermal and alternating field treatment with vector analysis. One magnetization (C) with low unblocking temperatures (<350°C) is probably a goethite weathering component of Cretaceous age. It gives a direction at 291°, +75° (12 sites, k = 73, α95 = 5°) and a pole at 60°N, 170°E. Two other closely related magnetizations (A, detrital?) probably carried by magnetite (AM) and hematite (AH) respectively, yield directions of 265°,‐29° (k = 87, α95 = 4°) and 264°,‐26° (k = 53, α95 = 6°) with a combined pole at 16°S, 141°E (14 sites, K = 141, A95 = 3°). The two remaining magnetizations (B, red hematite pigment?)—a normal (BN) and a reverse (BR) component recognized in most specimens—have a combined direction of 273°,‐09° (k = 17, α95 = 10°) and a pole at 3°S, 138°E (13 sites, K = 26, A95 = 8°). C and A are prefolding (before Paleocene or pre‐late Cretaceous) with A suggested to be primary. A and B lie close to a recently proposed polar track for the late Helikian and Hadrynian and evidence suggests a magnetization age for A of 900 to 950 Ma.