Mafic dyke swarm is widely developed in Proterozoic continental lithosphere. The Gangou diabase dyke from the Xixia area, intruded into the Douling complex of the South Qinling belt, yields zircon UPb age of 731 Ma. It has low SiO2 content (49.02 wt.%-49.37 wt.%) and Mg^# (34.0–37.7) and shows characteristics of subalkaline tholeiite series. They show high ΣREE (155.5×10 ⁶–184.7×10⁶), weak negative Eu anomaly (SEu=0.88-0.93), slight depletion of Nb and Ta, and enrichment of LILE. Their major and trace element, Sr-Nd-Pb isotope and clinopyroxene compositions indicate that it originated from the partial melting of the asthenospheric mantle within-plate extension setting and was slightly contaminated by crust compositions. The similarities of formation age, petrogenesis, source characteristic and tectonic setting for Gangou diabase with mafic dykes in Wudang Block and mafic volcanic rocks in Yaolinghe Group indicate that the South Qinling belt underwent strong continental extension in Neoproterozoic during 796–685 Ma most likely correspondence to the breaking-up of the Rodinia supercontinent.

中文翻译：

---

南秦岭地带新元古代铁镁质堤的地球化学，Sr-Nd-Pb同位素组成和锆石U-Pb年代学

镁铁质堤群在元古代大陆岩石圈中得到了广泛的发展。来自西峡地区的甘沟辉绿岩脉侵入南秦岭带的豆岭群，产生锆石的UPb年龄为731 Ma。它具有较低的SiO2含量（49.02 wt。％-49.37 wt。％）和Mg ^＃（34.0–37.7），并显示出亚碱性硫铝榴石系列的特征。它们显示出高ΣREE（155.5×10 ⁶ –184.7×10 ⁶），弱的Eu负负异常（SEu = 0.88-0.93），Nb和Ta的轻度耗尽以及LILE的富集。它们的主要和微量元素，Sr-Nd-Pb同位素和斜辉石成分表明，它源自软流圈地幔板内延伸背景的部分熔融，并被地壳成分轻微污染。武当区块甘草辉绿岩与基性岩脉和尧陵河组基性火山岩的形成年龄，岩石成因，物源特征和构造背景的相似性表明，南秦岭带在796-685 Ma期间经历了新元古代的强大陆扩张。罗迪尼亚超大陆的分裂。