| 柴云,祁昌炜,李玉龙,马延景,赵明福,魏有宁,李成福.东昆仑南缘浪卡日埃地区中三叠世侵入岩锆石U-Pb年龄、地球化学特征及其地质意义[J].矿产勘查,2018,9(8):1473-1482 |
| 东昆仑南缘浪卡日埃地区中三叠世侵入岩锆石U-Pb年龄、地球化学特征及其地质意义 |
| Zircon U-Pb age, geochemical characteristics and geological significance of the intrusive rocks from Middle Triassic in the Langkariai area,south margin of east Kunlun |
| 投稿时间：2018-04-11 |
| DOI： |
| 中文关键词: 侵入岩 锆石U-Pb年龄 地球化学特征 东昆仑 |
| 英文关键词: intrusive rocks,zircon U-Pb age,geochemistry, East Kunlun |
| 基金项目:中国地质调查局项目(编号:12120114047501)资助。 |
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| 中文摘要: |
| 东昆仑南缘浪卡日埃地区侵入岩主要由黑云母闪长岩、石英二长闪长岩、黑云母石英闪长岩、黑云母花岗闪长岩组成。为确定该地区侵入岩的形成时代、源区性质和构造背景,对其进行了锆石U-Pb年代学、地球化学和构造环境研究,认为该地区花岗岩具高硅(SiO2 54.09%～66.83%)、高钾(K2O 1.97%～3.92%)、富碱(Na2O + K2O为4.9%～7.48%)的特征,岩石里特曼指数δ=1.69～2.36,属钙碱性系列；铝过饱和指数(A /CNK)=0.73～1.07,属准铝质—过铝质系列岩石；稀土总量中等(∑REE为148.58×10-6～252.76×10-6),轻稀土元素富集(LREE/HREE=11.59～17.53),轻、重稀土元素分馏明显((La/Yb)N=4.62～23.40),具负Eu 和负Ce异常特征。岩石中Rb明显富集,K、Th含量较高,Ba相对亏损,Ce、Hf、Zr、Y、Yb等明显低于洋脊花岗岩。LA-ICP-MS 锆石U-Pb测年表明,其形成年龄为(203.34±0.72)Ma,时代为中二叠世。以上特征表明,该区侵入岩属S型花岗岩,具有火山弧花岗岩的特征,属大洋洋壳向北俯冲阶段,地壳物质部分熔融的产物。 |
| 英文摘要: |
| The intrusive rocks in Langkariai area in the south margin of east Kunlun are mainly composed of black mica diorite, quartz diorite, black mica quartz diorite, and black mica granites. In order to determine their formation time, origin and tectonic background of the intrusion rocks in the region, the study of zircon U-Pb chronology, geochemistry and tectonic environment was carried out, and it was considered that the granite with high-silicon (SiO2 in the area was 54.09%~66.83%), the high-potassium (K2O was 1.97%~3.92%), and the characteristics of the rich-alkali[w(Na2O+K2O)were4.9%~7.48%],and the Reitman index in the rock was1.69~2.36,which was a calc-alkaline series. The aluminum oversaturated index (A/CNK)=0.73~1.07, is A semi-aluminum series of rocks, Medium total rare earth (∑ REE = 148.58×10-6 ~ 252.76×10-6), enrichment of light rare earth element (LREE/HREE=11.59~17.53), light and heavy rare earth elements fractionation obviously [(La/Yb)N=4.62~23.4), negative Eu anomaly characteristics and negative Ce. The Rb of the rock is obviously rich, K, Th, and the relative loss of the Ba, Ce, Hf, Zr, Y, and Yb are obviously below the ridge of the ocean ridge. The u-pb dating of the LA-ICP-MS zircon shows that the formation age is 203.34±0.72Ma, which is the middle Permian. Intrusive rocks above characteristics show that the region belongs to S-type granite, has the characteristics of volcanic arc granite, belong to the ocean crust subduction northward stage, crustal material products of partial melting. |
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