李志琛. 1994: 敦煌地块变质岩系时代新认识. 地质通报, (2).
    引用本文: 李志琛. 1994: 敦煌地块变质岩系时代新认识. 地质通报, (2).
    LI Zhi-chen. 1994: NEW SPECULATION OF THE AGE OF THE METAMORPHIC ROCK SERIES OF THE DUNHANG MASSIF. Geological Bulletin of China, (2).
    Citation: LI Zhi-chen. 1994: NEW SPECULATION OF THE AGE OF THE METAMORPHIC ROCK SERIES OF THE DUNHANG MASSIF. Geological Bulletin of China, (2).

    敦煌地块变质岩系时代新认识

    NEW SPECULATION OF THE AGE OF THE METAMORPHIC ROCK SERIES OF THE DUNHANG MASSIF

    • 摘要: 敦煌地块的中深变质岩系敦煌群,经1/5万区调获得Sm-Nd等时线年龄值2935Ma、2946Ma、3487Ma,归属于太古界。北山南带的中深一浅变质岩系,经1/5万区调及1/20万区调修测,在中深变质岩系中获得Sm-Nd等时线年龄值2949Ma、2956Ma、3237Ma及2203Ma、2059Ma,分别划归敦煌群和厘定为早元古代。在浅变质岩系中获得Sm-Nd等时线年龄值1622Ma、1624Ma及Baicalia等叠层石,归属于中上元古界。

       

      Abstract: During 1:50000 regional surveys.the Dunhuang Group of the intermediate-and high- grademetamorphic rock series in the Dunhuang massif was determined to have Sm-Nd isochron age val-ues of 2935Ma , 2946Ma and 3487Ma,belonging to the Archean, Samples from the intermediate-and high-grade metamorpnic rock series in the south zone of the Beishan Mounains gave Sm-Ndisochron age values of 2949Ma,2956Ma,3237Ma ,2203Ma and 2059Ma,which are respectively as-signed to the Dunhuang Group and determined to be of Proterozoic age. Stromatolites such asBaicaliia were collected from the low-grade rock series and ages of 1622 Ma were obtained,so theseries is assigned to the middle Upper Proterozic.

       

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