长江中下游成矿带庐枞盆地科学深钻中侵入岩年代学及地球化学研究

发布时间：2018-04-30 22:01

本文选题：庐枞火山岩盆地 + 科学钻　；参考：《地质学报》2017年07期

【摘要】：庐枞盆地科学钻LZSD-01是"深部探测与实验研究"专项在庐枞盆地施工的中国大陆科学钻预导孔,该钻孔终孔深度3008.29m,成功揭露了庐枞盆地的深部地质结构。本次工作对科学钻深部的隐伏正长-二长岩开展了系统的年代学、岩石学及地球化学研究。结果表明,钱铺隐伏正长-二长岩锆石U-Pb年龄分别为132.6±1.2 Ma、133.28±0.4 Ma,属于盆地砖桥火山旋回末期岩浆侵入活动的产物。岩浆岩具有硅近饱和、高铝、高碱富钾、低钛,富集Rb、K、Pb等大离子亲石元素,亏损Nb、Ta、Ti等高场强元素的特征,指示隐伏岩体为橄榄玄粗质岩石。结合Sr-Nd同位素特征,推测岩浆源区可能为EMI型富集地幔,元素的演化趋势显示斜长石、辉石、钛铁矿为主的矿物分离结晶作用可能是岩浆演化的主要机制。岩浆形成于板内伸展拉张的构造背景之下。
[Abstract]:The scientific drilling LZSD-01 of Luzong Basin is a Chinese continental scientific pilot hole constructed by "deep exploration and experimental research". The depth of the final hole is 3008.29 m, which has successfully exposed the deep geological structure of Luzong Basin. A systematic study of chronology, petrology and geochemistry has been carried out on the underlying syenite in the deep part of the scientific drilling. The results show that the zircon U-Pb age of Qianpu concealed syenite is 132.6 卤1.2Ma- 133.28 卤0.4Ma. it is a product of magmatic intrusion at the end of the Bian Qiao volcanic cycle in the basin. The magmatic rocks have the characteristics of near saturation of silicon, high aluminum, high alkali and rich potassium, low titanium, enrichment of large ion lithophile elements, such as RbPe Knu Pb, and depletion of high field strength elements, such as Nbtaita-Ti, indicating that the concealed rock body is olivine coarse rock. Based on the Sr-Nd isotopic characteristics, it is inferred that the magmatic source region may be EMI enriched mantle, and the evolution trend of elements shows that the separation and crystallization of minerals dominated by plagioclase, pyroxene and ilmenite may be the main mechanism of magmatic evolution. The magma was formed in the tectonic setting of intraplate extensional extension.
【作者单位】：合肥工业大学资源与环境工程学院;安徽省地质调查院;中国地质科学院地质研究所;
【基金】：国家自然科学基金项目(编号41320104003) 中国地质调查局地质调查工作项目(编号12120114038001、1212011120862、12120114039701) 深部探测与实验研究专项(编号SinoProbe-05-05) 安徽省公益性地质调查项目(编号2016-g-2-16)共同资助的成果
【分类号】：P588.12

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