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扬子克拉通陆核位于湖北西部宜昌和神农架地区,区内出露了前寒武纪早期结晶基底和较完整的元古宙-显生宙沉积盖层.论文报道了对区域内中元古代至早古生代沉积地层细粒沉积岩开展系统的Nd同位素地球化学研究的结果.从中元古代晚期经新元古代南华纪至古生代奥陶纪,研究区沉积地层的Nd同位素模式年龄显示了由2.5~2.8Ga,经1.5~1.7至1.8~2.1Ga的“V”字型演化,相应的εNd(t)值发生了由低(?11~?14)经峰值(?1.1~?5.3)至新低值(?7.9~?9.9)的变化.该演化趋势与前人发表的扬子克拉通东南缘和江南造山带同期沉积地层的演化特征相似,指示了约0.8Ga的新元古代或稍早时期,整个华南陆块发生了有地幔物质加入的大规模构造岩浆事件.然而,扬子陆核区中元古代早期地层具有大范围变化的模式年龄(约1.5~2.7Ga)和εNd(t)值(1.38~?12.0),且中元古代晚期地层为太古宙模式年龄,指示扬子克拉通的核部和东南缘中元古代盆地具有不同的沉积物源,两区域之间应存在陆内裂(凹)陷或分隔的大洋.此外,新元古代扬子陆块和江南造山带相似的演化形式和古生代早期地层相近的模式年龄,指示经约0.9Ga的扬子-华夏陆块拼合后,华南陆块开始具有了共同的沉积盆地和物源.因此,扬子克拉通于前新元古代可能由次一级的不同陆块组成,直至Rodinia超大陆的聚合过程才导致了原始华南陆块的形成.
The Yangtze craton nucleus is located in the Yichang and Shennongjia areas in western Hubei Province, where the Precambrian crystalline basement and the more complete Proterozoic-Epitocene sedimentary cover are exposed. Early Neoproterozoic sedimentary stratigraphic fine sedimentary rocks to carry out systematic Nd isotope geochemical study results from the late Paleoenzoic Neoproterozoic Nanhua to Paleozoic Ordovician, the study area sedimentary strata Nd isotope pattern age shows that the 2.5 ~ 2.8Ga , And the corresponding εNd (t) values changed from low (from 11 to 14) through the peak (from 1.1 to 5.3) to new low values by the “V” shape of 1.5-1.7 to 1.8-2.1Ga. (? 7.9 ~? 9.9), which is similar to the evolutional characteristics of the sedimentary strata in the southeastern margin of the Yangtze craton and the Jiangnan orogenic belt in the past, indicating an evolution of about 0.8Ga Neoproterozoic or earlier period, Large-scale tectono-magmatic events with mantle material addition occurred in the southern China block. However, the model ages (~1.5 ~ 2.7Ga) and εNd (t) of the Mesoproterozoic meta- ? 12.0), and the Late Mesozoic and Late Stratum Archean model age, indicating the Yangtze carat The Mesozoic and southeastern margin of the Paleoproterozoic metamorphic sediments have different sedimentary provenances, and intraocular clefts (dimples) or separate oceans should exist between the two regions. In addition, the Neoproterozoic Yangtze block is similar to the Jiangnan orogenic belt The evolution pattern is similar to that of the early Paleozoic strata, indicating that the southern China block began to have a common sedimentary basin and provenance after the assembly of the Yangtze-Huaxia landmass of about 0.9 Ga. Therefore, the Yangtze craton may be related to the previous Neoproterozoic It is composed of different sub-level land masses and the polymerisation of the Rodinia supercontinent led to the formation of the original South China landmass.