论文部分内容阅读
吕梁地区界河口群主要由变泥砂质岩石和一定数量的大理岩及少量斜长角闪岩等类岩石组成。 7个变泥砂质岩石样品分析 ,ΣREE=15 2～ 32 2μg/ g,Eu/ Eu* =0 .2 4～ 0 .5 8,( L a/ Yb) n=8.9～ 12 ,Ba/ Ba* =0 .18～ 0 .71,Nd同位素亏损地幔模式年龄 t DM=2 .5 0～ 2 .77Ga。变泥砂质岩石给出 2 .80± 0 .11Ga和 2 .0 3± 0 .0 5 Ga两组 (变质 )碎屑锆石年龄数据。研究表明 :界河口群具孔兹岩系的性质 ,形成于古元古代 ,而不是新太古代 ,更不是中太古代的地质产物。界河口群很可能形成于华北太古宙克拉通被动大陆边缘的构造环境 ,其源区物质主体由新太古代富铝富钾的花岗质岩石和 /或碎屑沉积岩构成 ,但不排除少量中太古代物质参与的可能
The Lüliang area boundary estuarine group consists mainly of altered siltstone rocks, a certain amount of marble and a small amount of plagioclase amphiboles. Seven samples of siltstone changed from ΣREE = 15 2 ~ 32 2μg / g, Eu / Eu * = 0.24 ~ 0.58, (L a / Yb) n = 8.9 ~ 12 and Ba / Ba * = 0 .18 ~ 0 .71, Nd isotopic depletion mantle model age t DM = 2.5 ~ 2 .77Ga. The altered siltstone gives zircon age data for the 2.80 ± 0.11 Ga and 2.03 ± 0.05 Ga formations (metamorphic) clasts. The study shows that the nature of the Kongheizi faulted community is formed in the Paleoproterozoic, not the Neo-Archean, and not the Meso-Archean geology. The boundary estuary is likely to be formed in the tectonic setting of the margin of the passive continental margin of the Arctic Cosmos in North China. The source materials are composed of neo-Archean Al-K-rich granitic rocks and / or clastic sedimentary rocks, Possibility of Archean material involvement