Abstract:
The detailed geological survey shows that Suxiong Formation in Xiaoxiangling area of western Yangtze Block, consists of thick acid-intermediate acid lavas, volcaniclastic rocks and a small amount of basic lavas. And for the first time, four ancient volcanic apparatuses were found on both sides of the ridge of Xiaoxiangling Mountain. The volcanic apparatus in Yangnuo Snow mountain is the most grand, typical and complete sight and consists of volcanic neck facies, effusive facies, explosive facies and volcanic sedimentary facies. Systematic study of geological profile revealed that there were two eruption cycles, including fifteen volcanic rhythms, and there was a distinct period of volcanic intermission between these two eruption cycles. The discovery of these ancient volcanic apparatuses in Xiaoxiangling area can be used for further determination of volcanic eruption pattern and construction feature of Suxiong Formation. And this discovery can be also of significant importance to the study of the source of acidic volcanic rocks of Suxiong Formation and intracontinental riftimg in Neoproterozoic Era.