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Numerous minette dykes intersect the Precambrian crystalline basement of Schirmacher Oasis, East Antarctica. This study presents new Sr, Nd, Pb and O isotope data for 11 minette samples from four different dykes. The samples are characterized by relatively high Sr-87/Sr-86 (0.7077 0.7134), Pb-207/Pb-204 (15.45 15.55) and Pb-208/Pb-204 (37.8 39.8), combined with low Nd-143/Nd-444 (epsilon (Nd) = - 6.5 to - 25.1) and variable Pb-206/Pb-204 (16.8-18.1). The delta O-18 values are high, ranging from +6.5 to +9.5 parts per thousand SMOW Rb/Sr whole-rock biotite isochrons suggest an age of similar to 455 Ma for emplacement of the minette dykes. The major and compatible element geochemistry, of the minettes indicates derivation of the magmas from a mantle source. The enriched isotopic and trace element signatures of the dykes cannot be due to contamination of the ascending magmas by continental crust. Rather, the geochemical characteristics of the minettes are most reasonably explained by partial melting of a lithospheric mantle source that was enriched br metasomatic fluids derived from recycled continental crust. If mantle enrichment took place just before dyke emplacement, the isotopic systematics of the minettes must be inherited directly from the metasomatic agents, and this would indicate derivation of the fluids from recycled lower continental crust.