| The Humber Arm Allochthon was initially emplaced in the external Humber Zone of the Appalachian Orogen during the Early Ordovician, Taconian Orogeny, and further emplaced during the Devonian, Acadian Orogeny.; Sedimentary units were deposited during Precambrian rifting, Cambrian-Ordovician passive margin development, and at the onset of foreland basin deposition (the Curling, Northern Head, Pinchgut Lake, Goose Tickle and Table Head Groups) were mapped at 1:50,000 scale.; Five generations of structures are recognized based on overprinting criteria, mapping, and Argon isotopic dating techniques. D1 structures are dominantly west-directed thrusts and folds. D2 structures are east-directed folds and thrusts, age 455 Ma, and are interpreted as a loading event responsible for the creation of foreland accommodation space in the Late Ordovician. D3 structures are ductile and brittle normal sense faults, age 440 Ma, and associated with an Early Silurian foreland unconformity. D4 structures are open folds with steeply dipping axial surfaces. D5 is manifested as shallowly dipping east-west crenulation lineations. |
