腰深地区营城组火山岩相研究

Study on Volcanic Facies of Yingcheng Formation in Yaoshen Area

腰深2、3等井区营城组火山岩存在火山熔岩和火山碎屑岩两大类共15种具体岩石类型。岩性以酸性的流纹岩、凝灰岩、火山角砾岩为主。经井震结合分析得出,本区火山岩岩相存在5相6亚相类型,以喷溢相发育最为广泛。剖面上体现出爆发夹溢流的特点,远离火山口处溢流相和火山沉积相相互叠置出现,且该区块火山活动频繁,发育多期次火山活动,形成了多期喷发模式;平面上具有叠合连片的展布特点,火山喷发相隔较近时,爆发相往往连片展布,溢流相在熔岩台地上展布。

Yingcheng formation volcanic in Yaoshen area is classified as lava and pyroclastic rock, concluding 15 kinds of specific rocks, acidic rhyolite, tuff and volcanic breccia are main types. By combining logging and seismic, volcanic lithofacies can be divided into 5 categories and 6subfacies.The result shows that effusive facies is the main lithofacies in the study area.In profile, eruption is combined with effusion, and effusion and sedimentary facies are overlapping far away form the crater of the volcano. In this area, volcanic actives very frequently, developing many times of volcanic activity and eruption modes.The planephasing shows orerlaping phenomenon, when volcanic eruptions between the other one, eruption facies are throughgoing everywhere and effusion facies are overlapped on lava plateau.