LAUSR

Abstract The Abu Dabbab rare-metal granite in the Central Eastern Desert of Egypt is a peraluminous alkali-feldspar leucogranite stock with minimummelt composition of albite-rich haplogranite and is characterized by economic resources of columbite group minerals (CGM) and cassiterite. The bulk-rock trace element composition is characterized by very low Sr, Ba, REE+Y, Zr, Ti, Ni, Cr concentrations, elevated Li and F, and very high Sn, Ta and Ga. The non-chondritic, low Y/Ho ratios and extremely low Nb/Ta and Zr/Hf ratios of the Abu Dabbab granite are consistent with highly evolved peraluminous granites. The chondrite-normalized REE patterns with significant tetrad effects (TE1,3 ~ 1.6–2.6) and strongly negative Eu anomalies are indicative of the magmatic to hydrothermal transition. Heterogeneous 147Sm/144Nd (0.20411–0.51923) and 143Nd/144Nd (0.512968–0.514056) values of the bulk-rock reflect a disturbed Sm-Nd isotope system. Nevertheless, the initial eNd values calculated for a wide range of Neoproterozoic ages (500–700 Ma) are consistently positive, suggesting a juvenile source. Laser ablation ICP-MS analyses of the CGM, cassiterite, wolframite and Mn-ilmenite show elevated rare metal concentrations and complex REE tetrad patterns, reflecting fluid-melt interactions. The metasomatic fluids associated with the Abu Dabbab rare-metal granite were primarily low-salinity (