- 石油大学资源与信息学院，北京，102200
- 中国地质大学，北京，100083； 中国石油勘探研究院西北分院，兰州，730020
- 甘肃省地质调查院，兰州，730000
- 甘肃省地质调查院，兰州，730001
- Institute of Resources and Information, University of Petroleum, Beijing 102200
- (China University of Geology, Beijing 100083； Northwest Branch,Institute of Petroleum Exploration and Development of China, La nzhou 730020
- Institute of Geological Survey of Gansu Province, Lanzhou 730000
- Institute of Geological Survey of Gansu Province, Lanzhou 730001
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依据陇山群片麻岩的SmNd同位素资料, 认为片麻岩形成于中元 古代，等时线年龄为1451±190Ma，是裂谷作用初始阶段的火山沉积岩系。结合斜长角闪岩的地质、地球化学资 料及SmNd同位素资料，认为斜长角闪岩的原岩是侵入陇山群的辉绿岩墙或基性岩脉，不同 于陇山群的主体岩系，是800～1000Ma(晋宁期)裂谷作用的产物；源区为亏损的类似于现在 大洋中脊型地幔，裂谷活动的扩张速率为2～5cm/a，说明裂谷作用具有相当的规模。由于该区 位于祁连—秦岭造山带和贺兰裂谷的交叉位置，上述认识具有区域构造意义。
Based on new SmNd isotope data of gneisses in Longshan Group , we come to t he conclusion that Longshan Group formed in the Middle Proterozoic with an SmNd isochron age of 1451±190Ma, indicating an inicial rift magmatism in the region. Two more basic magmatisms took place afterwards with amphibolite SmNd isochro nages of 983±22Ma and 756±97Ma respectively, namely during Jinning Movement (8 00～1000Ma), and with materials very depleted and similar to MORBtype mantle s ource, reflecting intensive rifting. It′s also mentioned that owing to its speci al geological site of the studying area where QilianQinling orgenes and Helan rift meet, all the achievements mentioned above have much more regional tectonic significance.
引用本文
吴茂炳,郭彦如,刘春燕,左国朝.2002.甘肃东部陇山群的Sm-Nd年龄及其构造意义[J].地质论评,48(SUPP):59-63,[DOI].
Wu Maobing, Guo Yanru, Liu Chunyan, Zuo Guochao.2002. Study on SmNd Isotope Chronology of Longshan Group and its Tectonic signifi cance, Eastern Gansu Province, China[J]. Geological Review,48(SUPP):59-63.
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