ABSTRACT
The Shuiquangou complex is elongated in an east-west direction, which accords with the direction of deep-fault. It is characterized by enrichment in alkali and Fe and poor in Ca. The petrochemical characteristics indicate that the complex is a potassic to high-potassic complex consisting of cala-alkaline, weakly alkaline and alkaline rocks. Their petrochemical diagrams, REE and trace elements patterns show that the magma has two evolutional trends: acid (pyroxene diorite → amphibole monzonite → quartz alkali-feldspar syenite → alkali-feldspar granite) and alkaline (syenite → aegirine-augite syenite → alkali-feldspar syenite). The relatively high concentration of Ba, K, Sr and Hf with relatively low concentrations of Rb, Th, Nb, P and Ti implies that it should orignate from the mixed source region of mantle and crust. The calculation based on the 87Sr/86Sr ratio gives a mixing proportion: 62% upper mantle materials and 38% crustal materials, which suggests that the primary magma derived from the transition of the upper mantle and lower crust.
