下扬子区早二叠世孤峰期泥化火山岩

下扬子区早二叠世弧峰组是以层状硅岩为主的海相层系，厚度为２０－８０ｍ。在硅岩层间产出火山岩，火山岩夹层的厚度小但层数众多，并几乎已全部泥化。但仍保留着残留的流动构造；长石、磷灰石、黑云母、角闪石等矿物或其晶屑以及各种形态的玻屑。在大量蒙脱石、伊利石、绿泥石等因泥化而形成的火山岩中特征性矿物。根据宏观及显微镜下特征、岩石化学成分的不同特征进行判断，火山岩包含有基性熔岩、酸性凝灰岩，还有大量含火山碎屑

EARLY PERMIAN GUFENGIAN ARGILLIZED VOLCANICS IN THE LOWER YANGTZE REGION

There occur volcanic rocks in the Early permian Gufeng Formation in southern Jiangsu and Anhui and western Zhejiang in the lower Yangtze region. They are interbedded with black cherts; the beds are thin and numerous. The volcanic rocks consist of basic lavas, acid tuffs, and tuffaceous sedimentary rocks. Almost all of them have been argillized but there are still some recognizable characteristics of the textures, structures and mineral composition of volcanics. The intercalated cherts show no marked alteration though the volcanics have been argillized bed by bed. Therefore, the argillization of volcanic rocks is primary low-temperature hydrothermal alteration occurring on the sea floor. The above indicates the occurrence of submarine volcanic-hot spring activity in the region in the Gufengian stage.