Sedimentology and tectonic implications of the Pointe la Nim and Campbellton formations, western Chaleur Bay, maritime Canada.

Abstract

The middle to late Emsian clastic succession of the western Chaleur Bay region comprises the newly defined Pointe la Nim Formation and the overlying Campbellton Formation. The type and orientations of the fluvial systems present in the succession lends insight into the larger scale basin configurations and the nature and timing of major allocyclic events. The succession documents a transition from synvolcanic to syntectonic fluvial sedimentation related to a transition from subduction related island arc volcanism to uplift and dissection of the volcanic arc during the early stages of the Acadian Orogeny. The middle Emsian Pointe la Nim Formation is composed of interbedded extrusive volcanics, pyroclastics, and a wide range of fluvial deposits which exhibit a southwestwards to northeastwards proximal to distal trend. The mid to late Emsian Campbellton Formation overlies the Pointe la Nim Formation with local discordance, and can be subdivided into four distinct members: the lacustrine Atholville Member and the fluvial Pointe a la Garde, Pointe a Bourdeau, and Restigouche Members. (Abstract shortened by UMI.)