島根県桜江町北西部に分布する漸新統桜江層群

The Oligocene Sakurae Group consists of basalt lavas，dacitic pyroclastic rocks，dacitic welded tuffs and andesite lavas, in ascending order. This group is probably in fault contact with the basement Sangun metamorphic rocks，and forms a gentle half basin and not ar esurgent dome. Some dikes and plutons are emplaced along the faults. These structural characters suggest the formation of a cauldron closely related with the volcanic activity producing the Sakurae Group. NNW-SSE Strike slip faults cut the Sakurae Group after the formation of the cauldron.13;