Upper Devonian to Permian

The Upper Devonian and Carboniferous comprise a southern and a northern succession separated by the Ancestral Aklavik Arch. The southern succession, deposited in the Mackenzie Basin and the Prophet Trough, consists of Frasnian to Gzhelian strata. The northern succession comprises Viséan to Moscovian strata that onlapped the Yukon Fold Belt from the Prophet Trough. Both packages comprise marine to continental siliciclastics overlain by basinal to supratidal platform and ramp carbonates. The northeast-trending Late Devonian Mackenzie Basin and its Carboniferous successor, the Prophet Trough, developed in the foreland of a continental margin volcanic/plutonic belt and bifurcated in the north at the Yukon Fold Belt. During the Late Devonian and Tournaisian, the compressional northeast arm of the Mackenzie Basin/Prophet Trough lay southeastward of the Yukon Fold Belt, which resulted from a predominantly Late Devonian orogeny. Post-Tournaisian subsidence in the Prophet Trough resulted from extension. The Permian (Asselian to Wordian) overlies a latest Carboniferous to Early Permian unconformity. It comprises basinal to peritidal siliciclastics, carbonates, and chert that onlapped the Ancestral Aklavik Arch from the Ishbel Trough and were deposited in an unnamed basin to the north. The extensional Ishbel Trough succeeded the Prophet Trough and extended northward to the northeast-trending latest Carboniferous and Permian Ancestral Aklavik Arch of block-faulted origin, which developed across the southern Yukon Fold Belt. Frasnian to earliest Tournaisian climates were tropical; those of the Late Permian were temperate, thereby, indicating a northward shift of the region.