Abstract The lead isotope systematics of the ∼2715 Ma Kidd Creek volcanic-associated massive sulfide deposit and the host volcanic stratigraphic succession have been determined. The average ore lead isotope composition of eight galena samples from a variety of ore types and locations is 206 Pb/ 204 Pb = 13.258, 207 Pb/ 204 Pb = 14.443, and 208 Pb/ 204 Pb = 33.094. Single-stage model parameters for the ore are μ , ( 238 U/ 204 Pb) = 8.36 and K ( 232 Th/ 238 U, ∼Th/U) = 4.10. This composition is slightly more radiogenic than 2725 to 2730 Ma volcanic-associated massive sulfide ores in the northern Abitibi subprovince and slightly less radiogenic than such ores from 2705 to 2700 Ma camps in the southern Abitibi. Lead isotope data for 14 whole-rock samples from the stratigraphic sequence have μ , = 8.54 ± 0.43, and K = 4.10 ± 0.25, and a 207 Pb/ 204 Pb- 206 Pb/ 204 Pb regression age of 2.65 ± 0.08 Ga (all 2 a errors). The μ , and K values and regression ages are identical within error when the galena average is included. Similarly, six rhyolite samples from the Kidd Creek footwall and the footwall of the nearby Chance deposit have μ, = 8.37 ± 0.69, K = 4.13 ± 0.54, and a regression age of 2.71 ± 0.14 Ga. The ages agree with U-Pb zircon ages for the stratigraphic sequence and ore deposit, and thus the μ and K values are the primary igneous values for the suite. The μ and K values for the ore and stratigraphic sequence are identical to those of the Abitibi mantle source at 2.71 Ga. The primitive mantlelike K values for the Kidd Creek stratigraphic succession are higher than those of all other Abitibi suites measured, including komatiite-dominant suites along strike with the Kidd Creek mine. Lower K values for the other suites may reflect derivation by fluid-influenced (arclike?) mantle partial melting, or clinopyroxene fractionation in tholeiitic magmatic systems, or contamination by rocks formed by such processes. The primitive mantlelike K value reflects the highest proportion of mantle-derived rocks among the volcanic-associated massive sulfide-hosting stratigraphic successions in the Abitibi. Samarium-neodymium isotope signatures were determined for eight mafic and ultramafic rocks. Less-altered samples have € Nd ( t ) of 2.13 to 2.84 (n = 5), and three least altered samples have depleted mantle model ages of 2.71 to 2.79 Ga, reflecting a recent derivation from a midocean ridge basaltlike mantle depleted in Sm with respect to a chondritic (or primitive) reservoir. The Nd isotope data are similar to those of most other pretectonic volcanic suites in the Abitibi subprovince, and along with the Pb isotope data, they do not detect an older crustal component. The residues and leachates of whole-rock samples from leaching experiments were analyzed for their Pb and Nd isotope compositions. When grouped into cogenetic suites by area, these data plot as regression lines with younger ages at ∼2.54 to 2.53 Ga and ∼2.47 to 2.46 Ga. These younger regression ages postdate peak metamorphic conditions at 2.66 Ga and reflect thermal events documented elsewhere in the Abitibi and in the southern Superior province, including the Matachewan-Hearst dike swarm event at 2.45 Ga.