中文摘要：

西昆仑布隆二长花岗岩出露于西昆仑库地蛇绿混杂岩两侧。地球化学特征显示，布隆二长花岗岩主要为高钾钙碱-钾玄岩系列、过铝质花岗岩（A／CNK=1．1）。岩石具有低的Rb／Sr（0．67—0．88）、Sr／Y比值（13．2～16．6），弱的负Eu异常（Eu／Eu’=0．68～0．84）和中等Sr（214×10-6～247×10-6）、Rb含量（165×10-6～191×10-6），指示布隆二长花岗岩主要为黑云母和角闪石脱水熔融源区，其原岩可能来自于杂砂岩或壳源中性岩类。LA-ICP—MS锆石U—Pb定年结果显示该花岗岩的结晶年龄为441±2Ma（MSWD=0．33）。锆石的ε-Hf（t）值（平均值为-3．0）和Hf两阶段模式年龄值（1493—1116Ma）反映该花岗岩来自于中新元古代地壳的熔融。新获得的资料显示，西昆仑早古生代花岗岩均发育于库地蛇绿混杂岩两侧，且具有多个期次：507—500Ma、471～468Ma、447—430Ma和408～404Ma，推测西昆仑早古生代花岗岩为古特提斯洋在该地区长期俯冲的背景下形成的产物。

英文摘要：

This study reports geochemistry, zircon U-Pb and Hf-isotopic data for the monzogranite from the Bulong pluton, west Kunlun. The monzogranites are high-K calc-alkaline to shoshonitic series,with A/CNK values of 1.1. Their low Rb/Sr（0.67 ～ 0. 88 ） and Sr/Y ratios（ 13.2 16.6）, weakly negative Eu anomaly （Eu/Eu ＊= 0. 68 ～ 0.84）, and moderate Sr, Rb contents （ Sr = 214 × 10-6 ～ 247 × 10-6, Rb = 165 × 10-6 ～ 191× 10-6 ） indicate dehydration melting of biotiteand amphibole in the source region. LA-ICP-MS U-Pb zircon dating of the Bulong monzogranite yielded age of 441 ＋2 Ma（ MSWD = 0.33 ） with 8s~（t） values between -5.1 and -2.3 （ average value of -0.3 ）. The inferred protolith is an intermediate crustal igneous rock formed during the period of Mesoproterozoic-Neoproterozoic. Combined with the previous studies,it is suggest that the Early Paleozoic granites distrubuted at both sides of the Kudi ophiolitic melange and almost simultaneous with the Kudi ophiolitic melange. Early Paleozoic granites from the west Kunlun display multi-episodes with forming ages of 507 ～500 Ma, 471 ～468 Ma, 447 ～ 430 Ma and 408 ～404 Ma,which is probably the result of northward subduetion of the Paleo-Tethys ocean.