Interpretation of Regional Geophysical Data Acquired at the Bathurst Mining Camp, Canada

Abstract

The Bathurst Mining Camp is a major base-metal mining district in New Brunswick, Canada that was a focus area for the Geological Survey of Canada Targeted Geoscience Initiative Phase 3 project. As part of this project, more than 3500 gravimetric observations were acquired in the Bathurst Mining Camp, with an average spacing of 1-2 km, in 2006. The gravimetric data was reduced for an average crustal density value of 2.77 g/cm3 to obtain the Bouguer anomaly, which was analyzed and used to obtain 2.5D gravity models along five transects crossing the Bathurst Mining Camp. As a result of gravity modeling, a model of the general geometry of the main geological groups of the Bathurst Mining Camp (Fournier, California Lake, Tetagouche, and Miramichi) was obtained, which suggests that the Nine Mile Syncline is an open fold, and the Tetagouche Anticline is a gentle fold. Both folds are non-cylindrical and inclined, with their axial planes dipping in the 293° N direction: the angle of vergence of the folds increases towards the northeast of their axes. The structures under the Tetagouche Anticline axis gradually get deeper towards the Northeast reaching a maximum depth of 4 km. The depth of the structures modeled under the axis of the Nine Mile Syncline varies between 2 and 9 km, the deepest part being towards the center of the Bathurst Mining Camp; towards the northeast of its axis, the structures reach an intermediate depth of 4 km while towards the southwest they are 2 km deep on average.