The Duke River area comprises Late Paleozoic arc volcanic and sedimentary rocks, Triassic basalts, carbonate and sedimentary rocks, overlain by Tertiary terrestrial sedimentary and volcanic deposits. These rocks are intruded by Upper Triassic to Miocene plutons, sills and dykes. Post-late Paleozoic uplift and erosion are suggested by the lack of Early Triassic rocks, as well as a higher degree of folding exhibited by the older stratigraphy. A subsequent, compressional episode thrust Paleozoic rocks over Triassic rocks and folded the strata into upright, to overturned, tight folds. This event is younger than the Upper Triassic to Cretaceous Tatamagouche succession, but older than mid-Cretaceous plutons. Post-Cretaceous, steeply dipping strike-slip faults dissect the area and include both extensional and compressional components. A recent compressional event is exhibited by Triassic rocks thrust over folded Tertiary strata. The structural complexity of the area is significant, as it affects exploration targeted at mineralized Upper Triassic ultramafic intrusions.