【摘要】 大同地区密集分布的岩墙群由基性-超基性煌斑岩和碳酸岩组成,侵入于石炭-二叠纪煤层中。与地层的接触关系和Rb-Sr、K-Ar同位素年代学数据表明岩墙群的侵位于晚三叠世。Sr、Nd同位素比值显示,碳酸岩和煌斑岩都来源于壳幔混合型岩浆源区。稳定元素比值和相容、不相容元素同等富集则表明它们是碳酸岩和硅酸盐混合的原始母岩浆液态不混熔的产物。岩墙群形成的地质条件和构造背景表明,它们是在伸展构造背景下,受到不同级别的构造控制。大同岩墙群的研究对进一步认识华北早中生代岩石圈演化有重要的意义。更多还原

【Abstract】 In the Carboniferous-Permian coal formations in Datong area lots of basic dike warms occur. They are mainly carbonatites and basic-ultrabasic lamprophyres. The strata, relationships as well as Rb-Sr and K-Ar isotopic chronology show that the dike swarms were formed at Late Triassic(229Ma). The Sr、Nd isotopic ratios and Rb/Sr ratios of carbonatites and lamprophyres indicate that they were originated from a crustal-mantle mixing type reservoir. The stable element ratio of compatible and incompatible elements implies that they are liquid immiscible congeners coming from a primitive magma consisting of mixed carbonatites and silicates. Examination of the conditions reveals that they were formed in extensional tectonic sittings and controlled by structures at different levels. Study on Datong dike swarms will play an important role in further understanding the evolution of the Early Mesozoic lithosphere in North China.更多还原