Abstract

Pink Mountain Anticline stands out in front of the foothills of northeastern British Columbia (57°N, 123°W). Geologic mapping and prestack depth-migrated seismic sections show that it is localized above and west of a northwest-trending subsurface normal fault. Along with isopach maps these data demonstrate episodic normal movement on the fault during deposition of the Carboniferous Stoddart Group, Triassic Montney Formation and possibly the Jurassic–Cretaceous Monteith–Gething formations. West of this fault, during Laramide compression, a pair of backthrusts nucleated on either side of a minor east–west trending Carboniferous fault and propagated across it in an en echelon pattern. One backthrust ramped laterally across the area and separated the Pink Mountain and Spruce Mountain structures, both of which are contained within a 30+ km long pop-up structure above the Besa River Formation decollement.

Glomerspirella fossils confirm the existence of the Upper Jurassic Upper Fernie Formation and Upper Jurassic to Lower Cretaceous Monteith Formation at Pink Mountain.