Modern processing methods were applied to 3400 line-kilometres of legacy seismic data from Sabine Peninsula of Melville Island in the Canadian Arctic Islands. Post-stack reprocessing improved the imaging, allowing new insight into the following issues: the northern extent of lower Paleozoic source rocks, extensional structures and rock types in the upper Paleozoic succession, the timing of the gentle Drake Point Anticline; and the age and extent of igneous sills. The central part of Sabine Peninsula is underlain by a half-graben containing upper Paleozoic strata. The half-graben fill is intersected by just one well, but it likely contains Upper Carboniferous to Lower Permian strata. The two largest conventional gas fields in Canada (Drake Point and Hecla) are hosted in Mesozoic strata within a gentle anticline that partially overlies the half-graben. Previously, the Drake Point Anticline was interpreted to have been formed during Eocene time. We propose that 280 m of the 430 m of structural relief on the Drake Anticline formed in response to uplift at the axis of the anticline in the Early Cretaceous, as shown by thinning of the Lower Cretaceous Christopher Formation over the Drake Anticline. The remaining 150 m of structural relief formed by differential movement between the Marryatt Point Syncline and Drake Point Anticline after the Early Cretaceous. Early Cretaceous relief on the Drake Point Anticline means it was at least partially present at the time of maximum hydrocarbon generation in the Late Cretaceous.