赣南—粤北中生代晚期火山旋回的划分

Division of Volcanic Activity Cycles in the Late Mesozoic in South Jiangxi and North Guangdong

根据地层的接触关系、岩石组合、化石组合、同位素年龄及构造特征，赣南—粤北中生代晚期火山活动，可划分出余田、莲花寨、版石和南雄四个火山旋回。余田火山旋回发育于中侏罗世，由玄武岩－流纹岩组成“双峰式”岩石组合；莲花寨火山旋回发育于晚侏罗世，由流纹岩组成“单峰式”岩石组合；版石火山旋回发育于早白垩世晚期—晚白垩世早期，岩石组合较复杂，既有由流纹岩或玄武岩组成的“单峰式”岩石组合，也有由少量玄武岩和大量流纹岩组成的“不对称双峰式”岩石组合；南雄火山旋回发育于晚白垩世晚期，由玄武岩组成的“单峰式”岩石组合夹于红色沉积岩系中。

Based on stratigraphical unconformity, rock association, fossil assemblage, isotope age and tectonic features, the volcanic activity in late Mesozoic in south Jiangxi and north Guandong can be divided into four cycles: Yutian volcanic activity cycle, Lianhuazhai volcanic activity cycle, Banshi volcanic activity cycle and Nanxiong volcanic activity cycle.Yutian volcanic cycle which occurs in middle Jurassic epoch is the bimodal rock association composed of rhyolite and basalt. Lianhuazhai volcanic cycle which occurs in late Jurassic epoch is unimodal rock association composed of rhyolite. Banshi volcanic cycle occurs from the late stage of early Cretaceous to the early stage of late Cretaceous epoch. There are two types of rock associations related to this cycle: unimodal rock association composed of rhyolite or basalt and bimodal rock association composed of rhyolite and basalt. Nanxiong volcanic activity cycle which occurred in late stage of late Cretaceous epoch is the unimodal rock association composed of basalt which is the interlayer of the red sedimentary series.