对辽宁兴城尖山火山机构的岩性- -岩相学特征进行了分析，并对角闪安山岩进行了岩石地球化学研究。结果表明角闪安山岩 SiO 2 = 58. 42% ～ 60. 42%，Al 2 O 3 = 16. 17% ～ 17. 5%，MgO = 1. 39% ～ 3. 08%，Mg # = 31 ～ 50，Sr = (387 ～ 1 325) × 10 ^－6 ，Yb = (1. 15 ～ 1. 57) × 10 ^－6 ，Y = (12. 1 ～ 16. 8) ×10^－6 。岩石富集轻稀土元素及大离子亲石元素，亏损高场强元素，高 Sr 和 Sr/Y 比值，低 Y 和 Yb，显示出埃达克岩的地球化学特征，但其 Mg # 较低，表明该类火山岩可能是加厚的基性下地壳部分熔融的产物，可能与早白垩世太平洋板块的俯冲构造背景有关。

The petrology and petrography of Jianshan volcanic mecganism in Xingcheng，Liaoning have been analyzed，and the geochemistry of hornblende andesites were studied． The results show that the hornblende andes- ites are characterized by SiO 2 =58. 42% ～60. 42%，MgO =1. 39% ～3. 08%，Mg # =31 ～50，Al 2 O 3 =16. 17% ～17. 5%， Sr = (387 ～1 325) ×10^－6 ，Yb = (1. 15 ～1. 57) ×10^－6 ，Y = (12. 1 ～16. 8) ×10^－6 ， respec- tively． In addition，the volcanic rocks are enrichment in LREE and LILE and depletion in HREE，with high Sr and Sr/ Y values and low Y and Yb values，showing the geochemical characteristics of adakite． However，they are low in Mg#，indicating the volcanic rocks may originate by partial melting of the thickened mafic lower crust，and could be related to the subduction of the Paleo- Pacific Plate beneath the Eurasian continent．