The geology of Nunavut began to form nearly three billion years ago in the Archean and the territory preserves some of the world's oldest rock units.
Greenstone belts are common together with migmatite gneiss, granodiorite, and quartz monzonite, on the Melville Peninsula and northern Baffin Island, as well as the southwest mainland.
Ultramafic volcanic rocks, quartzite and iron formations in the northern Churchill Province hold the Woodhurn, Prince Albert and Meadowbank gold deposits.
[2] Paleozoic rocks cover one-third of the territory, northwest of Fury and Hecla Strait, forming part of the Arctic Platform and continuing north to Ellesmere Island.
The Caledonian orogeny brought uplift and erosion from the Silurian through the Early Devonian, generating potential red bed related copper deposits in a thick clastic wedge.
The Borden Peninsula is divided into horst and graben structures by normal faults from local rifting and subsidence 1.27 billion years ago.
Through the Cretaceous, sedimentation continued in the Sverdrup Basin, producing oil and gas forming conditions and Bent Horn light crude field.