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南秦岭勉略古缝合带是一个构造混杂岩型非史密斯地层区，由不同时代的原地地层系统和异地地层系统的构造岩片构成。泥盆纪—石炭纪硅质岩的常量元素、稀土元素分析结果指示了勉略小洋盆的存在。区域背景分析表明晚震旦世到早寒武世，南秦岭为扬子板块北部边缘的一部分，中、晚寒武世以后开始分裂形成南秦岭裂陷槽。该海槽于中、晚志留世萎缩但未关闭，泥盆纪又进一步开裂逐渐形成大陆边缘裂谷盆地，晚泥盆世后期到早石炭世早期形成一开放小洋盆。早石炭世后期出现洋壳俯冲，从而转化为活动大陆边缘盆地。该洋盆可能持续到二叠纪，并于印支期最终关闭、碰撞和造山。
The Mouth of Qinling Ridge ancient suture is a structure of melange-type non-Smith stratigraphic zone, from the different age of the in situ formation system and the formation of different stratigraphic structure of rock slices. The major element of Devonian-Carboniferous chert, the result of REE analysis indicates the existence of Mianlue small oceanic basin. The regional background analysis shows that from late Sinian to Early Cambrian, the southern Qinling is a part of the northern margin of the Yangtze plate. After the middle and late Cambrian, the South Qinling rift began to divide. The trough in the late Silurian atrophy but did not close, the Devonian and further cracking gradually formed continental margin rift basin, late Late Devonian to Early Carboniferous formed an open small oceanic basin. The late Carboniferous oceanic crust subduction, which translates into active continental margin basins. The oceanic basin may continue into the Permian and eventually shut down during the Indosinian period, colliding and orogenic.