Abstract: The PhuPhaLek iron deposit, Laos in the northwestern part of the Truongson fold belt occurs as a large-sized skarn-type iron deposit. The mineralization occurs within the inner-outer contact zone of monzonite granite porphyries. The monzonite granite porphyries have enriched alkali and oversaturated Si and Al, and are assigned to the calc-alkaline rocks. The trace element distribution patterns are similar to those of the normal continental arc granites. The rare earth element distribution patterns display right-leaning LREE-enriched patterns with positive Eu anomaly and marked fractionation of LREE and HREE, suggesting the "S"-type granites created by the remelting and intrusion of the lower crust melts. The SHRIMP U-Pb age of 283±2.9 Ma indicates that the emplacement took place during the Early Permian.