Pre-Carboniferous geology of the northern part of the Arctic Islands: Northern Heiberg Fold Belt, Clements Markham Fold Belt, and Pearya; northern Axel Heiberg and Ellesmere islands

This report describes and interprets the geology of three tectono-stratigraphic belts in the northernmost part of the Canadian Arctic Archipelago that differ in structural trend and in aspects of their stratigraphy and tectonic histories. The southeast-trending Northern Heiberg Fold Belt of Axel Heiberg Island contains about 8 km of strata ranging in age from Early Cambrian or older to Early Devonian. The southwest-trending Clements Markham Fold Belt of northern Ellesmere Island contains 4 to 5 km of strata ranging from Early Cambrian or older to Late Silurian. Pearya is limited to northernmost Ellesmere Island and has highly diverse structural trends. It comprises a Mesoproterozoic crystalline basement and probably more than 8 km of supracrustal strata that extend in age from Neoproterozoic to Late Silurian. Pearya is interpreted as a suspect terrane with Caledonian affinities that probably was accreted to the Clements Markham Fold Belt in Late Ordovician time. The strata of all three provinces consist of a considerable variety of sedimentary and volcanic rocks that were partly metamorphosed under greenschist to lower amphibolite facies conditions. Orogenies of late Mesoproterozoic-early Neoproterozoic and Early-Middle Ordovician ages were confined to Pearya. Several disturbances occurred in Pearya and the Clements Markham Fold Belt in Late Ordovician-earliest Silurian time. A Late Silurian-Early Devonian orogenic event, apparent in the Northern Heiberg Fold Belt, probably also affected Ellesmere Island. The Late Devonian-Early Carboniferous Ellesmerian Orogeny involved the entire report area. Six generations of granitoid intrusions, ranging in age from late Mesoproterozoic to Late Devonian, are of synorogenic or postorogenic origin, whereas granitoid intrusions of late Early Carboniferous and Late Cretaceous ages are of rift origin. An ultramafic-mafic suite is of Early Ordovician age, and mafic plutons range in age from Ordovician(?) to Late Cretaceous. Small showings of copper minerals occur in volcanic and carbonate rocks of the Clements Markham Fold Belt and Pearya.