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The islands south of Parry Channel, except Banks, have a thin, discontinuous cover of Ordovician and Silurian carbonates, relatively undisturbed except for local north trending structures adjacent to the Boothia arch. Late Silurian or early Devonian fanglomerates near the arch were deposited contemporary with these movements. On northwestern Victoria and Banks islands a monoclinal section to the northwest reaches the Upper Devonian (which is clastic as in the northern islands) followed by marine Lower Cretaceous and non-marine Tertiary.
Queen Elizabeth Islands, north of Parry Channel, record heavier sedimentation and complex structural history. From Cambrian to Upper Devonian an arc-shaped geosyncline extended easterly through Parry Islands and then northeasterly through Ellesmere. Adjacent shelf regions are south Melville and Bathurst islands, most of Devon Island and southeastern Ellesmere Island. Cambrian, Ordovician, and Silurian rocks, locally at least 20,000 feet thick, are essentially carbonate and shale with some evaporates. Ordovician and Silurian carbonates occupy outer side of arc and shale the inner. North Ellesmere and northwesternmost Axel Heiberg have metasediments and volcanics, probably the contemporary eugeosyncline. The Devonian sequence 17,000 feet thick is mainly quartzose clastics locally with c rbonates in the lower part.
Cornwallis Island and neighboring coasts have northeasterly structures produced at time of movement on Boothia arch. Main body of geosyncline was deformed between Upper Devonian and Middle Pennsylvanian forming east-west structures in Parry Islands and northeasterly structures in Ellesmere. In middle Pennsylvanian the Sverdrup Basin, centered on Axel Heiberg Island, developed above the old eugeosynclinal belt and received about 50,000 feet of Pennsylvanian to early Tertiary sediments. The Permo-Pennsylvanian includes carbonates, shales and evaporites; the Mesozoic comprises alternating marine and non-marine sandstones and shales. In Mesozoic thin sandy deposits characterize basin margins, and shales the axis. Section on axis is essentially conformable, on margins it is incomplete from overstep and thinning. Early Tertiary rocks are entirely non-marine with coal seams, and are followed by orogeny that produced mainly northerly thrust faults and folds, also diapiric intrusion of Upper Paleozoic evaporites.
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