湖南省益阳市南郊石咀塘-桃花岭一带,元古界冷家溪群下部发育2000余米厚的变质基性火山岩系,出露面积达20km~2。该火山岩系以熔岩为主,呈岩流产出,其次为凝灰岩、层凝灰岩、火山角砾-岩屑凝灰岩;两个喷溢旋迴,第一旋迴出露完整,第二旋迴多被第四系沉积物所覆盖;并与其顶底的沉积变质岩系呈整合接触关系。第一旋迴火山岩系熔岩具典型的水下喷 The Shiyutang-Taohuawling area in the southern suburbs of Yiyang City, Hunan Province, developed metamorphic basement volcanic rocks more than 2,000 meters thick in the lower part of the Lengjiaxi Group in the Proterozoic. The exposed area is 20km ~ 2. The volcanic rocks are dominated by lava and produced rock flows, followed by tuffs, tuffs and volcanic breccias-lithic tuffs. The two volcanic cycles are exhumed, the first cycle is exposed, and the second cycle is dominated by Four series of sediments covered; and the top of the sedimentary metamorphic rocks were in integrated contact relationship. The first cyclonic volcanic lava with a typical underwater spray