1�� College of Earth Sciences��Jilin University��Changchun 130061��China; 2�� ��esearch Center of Palaeontology �� Stratigraphy��Jilin University��Changchun 130026��China

Zircon LA- ICP- MS U- Pb age and whole- rock geochemistry data are presented for the Dongxigao dio- rite porphyries in Pingyi��western Shandong��to restrict its petrogenesis�� The zircons from the Dongxigao diorite porphyries exhibit striped absorption and oscillatory growth zoning in the cathodoluminescence images��which have upward- type characteristics of rare earth elements (��EEs) with positive anomaly of Ce and negative anomaly of Eu��and have high Th/U ratios (0�� 06- 0.91)��indicating its magma origin�� Zircon LA- ICP- MS U- Pb dating indicates that 207 Pb/ 206 Pb ages of 16 spots of zircons are between 2 476 Ma and 2 701 Ma��yielding a weighted mean age of 2 481 ±8 Ma��which represents the formation age of Dongxigao diorite porphyries��i.e. Late Neoarchaean�� Geochemically��the samples have low contents of SiO 2 (54.94% and 54.86%) and high amounts of MgO (7.19% and 7.58%) and Mg # values (66�� 47 and 67�� 59)�� Additionally��the Dongxigao dio- rite porphyries show enrichment of L��EEs and prominent negative Eu anomaly (δEu = 0.89 and 0.91)��and they are characterized by enrichment of large ion lithophile elements (LILEs) (e.g. Cs����b and Ba)��deple- tion of high field strength elements (HFSEs) (e.g. Nb��Ta��Zr��Hf and Ti)��and positive anomaly of K and Pb�� The results imply that the Dongxigao diorite porphyries dominantly derived from partial melting of enriched lithospheric mantle with attributes of arc magma��and the magma source area was mixed with amounts of conti- nental crust material��it suggests that they formed in transformation tectonic setting changing from compression to intraplate extension��