中文摘要：

东准噶尔北缘老山口铁铜金矿区花岗质岩体主要有石英闪长岩、黑云母闪长岩、二长花岗岩、正长斑岩和闪长（玢）岩.对黑云母闪长岩和正长斑岩进行了岩石地球化学研究,结果表明：黑云母闪长岩SiO2含量介于54.43％～55.10％,Al2O3和CaO含量分别为16.92％～17.64％和5.35％ ～ 5.94％,Mg#值为（51.95 ～55.96）,富碱（K2O＋ Na2O =9.0％ ～9.43％）和高钾（K2O/Na2O=1.32～1.74）；与之相比,正长斑岩的SiO2 （59.96％ ～63.60％）、Al2O3（18.15％ ～ 19.13％）和Mg#（30.16 ～ 48.20）、全碱（K2O＋Na2O=11.81％～13.17％）含量偏高,CaO含量（1.13％ ～2.47％）和K2O/Na2O比值（1.1 ～1.53）偏低.它们属钾玄质系列岩石.所有岩石富集LREE和Rb、K、Pb、Sr和Zr,相对亏损Nb、Ta和Ti,是晚古生代准噶尔古大洋俯冲的产物.黑云母闪长岩是俯冲板片熔体和富含钾的地幔楔熔体深侵位的产物,正长斑岩为黑云母闪长岩原始岩浆经角闪石和辉石的分离结晶后又经钾长石堆晶和角闪石残余岩浆浅侵位的产物.

英文摘要：

The Laoshankou granitoids located on the northern margin of the Junggar, Xinjiang, are composed of diorite, adamellite, syenite porphyry and diorite （porphyrite）. Geochemical characteristics of biotite diorite and syenite porphyry show that the concentration of SiO2 of biotite diorite is 54.43% - 55.10%, A1203 16.92% 17.64% and CaO 5.35% - 5.94%. They are high in total alkali （K20 ＋ Na20） content （9.00% - 9.43% ） and enriched in potassic （ K20/Na20 = 1.32 - 1.74 ）. Compared with biotite diorite, the syenite porphyry is high in the concentrations of SIO2（59.96% - 63.60%）, A1203（18.15% - 19.13%） and Mg~（51.95 55.96）, total alkali （K20 ＋ Na20 = 11.81% - 13.17% ）, and low in the concentrations of CaO（1.13% 2.47% ） and Mg#（30. 16 - 48.20）, K20/Na20 ratio （1.1 - 1.53）. They are belong to shoshonitic high-K alkaline granitoids. In addition, they display noticeable enrichment on LREE, Rb, K, Pb, Sr and Zr, obvious depleted in Nb, Ta and Ti. These features, together with the regional geology characteristics, indicate that Laoshankou granitoids are formed under a subducted tectonic setting. The parental magma of syenite porphyry was residual melt left by elinopyroxene and amphibole fractional crystallization from biotite diorite parental magma derived from the mixed melt of riched potassium minerals mantle peridotites and subducted oceanic slab.