volcanic vent

They have both the flooding and the intrusive lithofacies but also have the volcanic and the volcano vent lithofacies and the lithology is mainly the middle acidic intrusive rocks.(既有溢流相，又有侵入岩相，还有次火山岩相和火山通道相；岩性主要以中酸性侵入岩为主。)

The scientists determined that the depression was a volcanic vent, and the bright ring around it was pyroclastic, remnants of lava that had been spewed outward, much like a volcanic fountain on Earth.(科学家确定凹陷处是一个火山口，并且在它附近明亮的圆环是火山碎屑岩，是火山喷发出岩浆的残余，很象地球上的火山喷口。)

The development features of reservoir space are different in different lithofacies belts. In a word, around volcanic vent is favorable reservoir development position.(不同岩相带储集空间的发育特征不同，火山通道周围是有利储集层发育区。)