Abstract

A paleomagnetic study was conducted on dike samples taken from three widely separated localities along the northeasterly trending Caraquet dike system (New Brunswick) in order to define their age relationship. This dike system is recognized on the basis of a well defined aeromagnetic lineament. Stable magnetization directions were isolated after alternating field (15–40 mT) and thermal (300–550 °C) treatments of the samples taken from the three localities: C (353°, +56°), N (353°, +50°), and T (14°, +37°). The virtual pole derived from dike T (82°E, 62°N) agrees well with previously determined Late Triassic – Early Jurassic (200–190 Ma) poles for the Appalachians. On the other hand, the other two virtual pole positions from dikes C (143°E, 78°N) and N (133°E, 74°N) fall in the general area of average paleopoles for the Middle–Late Jurassic (180–170 Ma) age. The possibility that the dike at T differs in age from that of the dikes at localities C and N by at least 20 Ma is suggested. In the absence of reliable radiometric data, it is premature at the present stage to predict a likely occurrence of "younger" magnetization in these dikes related in origin to viscous partial thermoremanence possibly associated with the rifting and opening of the Atlantic in Middle Jurassic. Further investigations on newly found diabase outcrops along the magnetic lineament are in progress.

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