The tectonic affinity of mid - late Neoproterozoic magmatism in the South China Block provides a first order constraint on its role in the break-up of Rodinia and the subsequent amalgamation of Gondwana. The Yingyangguan area in the western margin of Cathaysia Block preserves a magmatic and sedimentary record of this period. U-Pb zircon age data indicate magmatism at around 750 Ma, followed by accumulation of a succession of tuff and carbonate rocks at ca. 670–660 Ma. All samples show evidence for ductile deformation and metamorphism. The geochemical characteristics of mid-Neoproterozoic mafic and intermediate rocks suggest crustal assimilation and fractional crystallization play an important role in magma evolution, and they were derived from a source dominated by modified lithospheric mantle sources previously metasomatized by slab-derived fluids. Analyzed samples, as well as contemporaneous mafic rocks in neighboring areas, have high Zr/Y ratios, and plot in the within-plate basalt field at ca. 750 Ma. In addition, zircons with ages between 1200 and 950 Ma and 850–770 Ma mostly fall within the arc-related field on discriminating diagrams based on zircon trace-element compositions, whereas, most ca. 750 Ma and 700–600 Ma zircons plot in the within-plate field. This evolving tectonic record of magmatic activity suggests a transformation from a convergent plate margin setting on the periphery of Rodinia to one involving within plate extension at ca. 750 Ma. Furthermore, the detrital zircons from samples of the Yingyangguan Group present abundant late Mesoproterozoic to early Neoproterozoic (1200–950 Ma) ages. These ages match the record of North India and Indo-Antarctica, and imply a peripheral setting for South China with respect to the supercontinent and most likely adjacent to India from at least 750 Ma. Thus, we suggest that the Yangtze Block accreted to Cathaysia on the northern margin of India in the early Neoproterozoic, and that the active plate boundaries located along the northern and western margins of South China continue to ca. 750 Ma. After this time, the tectonic setting within the South China Block transformed into a stable within-plate siliciclastic depositional environment that continued to receive detritus from East Gondwana until the early Devonian.

华南地块中晚期新元古代岩浆作用的构造亲和力为其在罗迪尼亚解体和后来的冈瓦纳合并中的作用提供了第一级的约束。华夏地块西缘的营阳关地区保留了这一时期的岩浆和沉积记录。U-Pb锆石年龄数据表明岩浆活动在750 Ma左右，其次是大约20年代堆积的凝灰岩和碳酸盐岩。670–660马。所有样品均显示出韧性变形和变质的证据。中新元古代基性和中性岩石的地球化学特征表明，地壳同化和部分结晶在岩浆演化中起着重要作用，它们是由以前被板状流体交代的岩石圈地幔改良源主导的。分析后的样品以及邻近地区的同期镁铁质岩石均具有较高的Zr / Y比，并标绘在ca的板内玄武岩场中。750毫安。另外，在基于锆石痕量元素组成的判别图上，年龄在1200Ma和950Ma之间以及850Mas到770Ma之间的锆石大多属于弧相关领域。在板内场中绘制了750 Ma和700–600 Ma锆石。这种不断演变的岩浆活动的构造记录表明，从罗迪尼亚外围的收敛板块边缘位置转变为一个在约２００２年的板块内部延伸。750毫安。此外，营阳关组样品中的碎屑锆石具有丰富的中元古代晚期至新元古代早期（1200-950 Ma）年龄。这些年龄与北印度和南极印度洋的记录相符，并且暗示着华南处于超大陆的外围环境，并且最有可能在至少750 Ma与印度相邻。因此，我们建议扬子地块在新元古代早期就在印度北缘向华夏增生，而沿华南北缘和西缘的活跃板块边界一直持续到大约。750毫安。这段时间之后，华南地块内的构造环境转变为稳定的板内硅质碎屑沉积环境，继续接受东冈瓦纳的碎屑直至泥盆纪早期。