The Brock Inlier, Northwest Territories, comprises carbonate and siliciclastic sedimentary rocks of the early Neoproterozoic (~1000-720 Ma) Shaler Supergroup. Strata were deposited in a large embayment (Amundsen Basin), an epeiric sea within the supercontinent Rodinia. Strata in the Brock Inlier correlate with other inliers of the Shaler Supergroup to the northeast on Victoria and Banks islands, and with the Mackenzie Mountains Supergroup, in the northern Cordillera, to the southwest. The ~900 Ma Boot Inlet Formation, occurs stratigraphically in the middle of the Shaler Supergroup and facies are interpreted to represent deposition along a storm-dominated carbonate ramp. Delta 13C and Delta 18O data coupled with lithostratigraphic and sequence stratigraphic frameworks corroborate correlations with the Little Dal Group in the Mackenzie Mountains (~600km to the southwest). These early Neoproterozoic sedimentary rocks may record a transitional phase from low to high Delta 13C isotopic variability reflecting heightened sensitivity to fluxes caused by biogeochemical perturbations.