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，又有侵入巖相，還有次火山巖相和火山通道相；巖性主要以中酸性侵入巖為主。)

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.(科學家確定凹陷處是一個火山口，并且在它附近明亮的圓環是火山碎屑巖，是火山噴發出巖漿的殘余，很象地球上的火山噴口。)

The development features of reservoir space are different in different lithofacies belts. In a word, around volcanic vent is favorable reservoir development position.(不同巖相帶儲集空間的發育特征不同，火山通道周圍是有利儲集層發育區。)