| The present study has determined that tholeiitic basalt dykes, trending ∼130°, found near Tsu Lake, NT, are geochemically similar to the Sparrow Dyke Swarm (McGlynn et al., 1974). Geochemically, the correlation of the calc-alkaline basalts of the Martin Group Igneous Rock (MGIR) with the Sparrow (Morelli et al., 2009), is invalid as the former display higher incompatible element concentrations. Rather, the MGIR are geochemically similar to the ultrapotassic Christopher Island Formation (CIF).;Of these three suites, the Sparrow shows the least negative εNd, the CIF is the most negative and the MGIR is intermediate. Initial 87Sr/86Sr of these suites is similar within error. This is interpreted as evidence that the intensity of the metasomatism responsible for enriching the lithospheric mantle source of the CIF (Cousens et al., 2001) began to wane towards the SW, where the MGIR were sourced, and was minimal where the Sparrow swarm was sourced. |
