新疆北山晚古生代克拉通裂谷火山作用特征

新疆北山构造带克拉通裂谷活动期火山活动频繁,火山作用较强烈.区内晚古生代火山岩分布广泛,集中发育于下石炭统上部、上石炭统和下二叠统,与正常沉积岩呈断续间互层状产出.据岩石地层研究、火山岩产状及接触关系,划分为4个火山旋回,共9个火山喷溢韵律.在对区内火山岩地质特征、岩石类型、岩石化学和稀土元素地球化学特征研究基础上,探讨了火山岩的演化特点和形成环境.

Volcanism during activity period of Beishan craton rift in Xinjiang,China

The volcanic activities were frequent during the activity period of the craton rift in the Western Beishan Tectonic Belt, Xinjiang, and the volcanism was strong too. The volcanic rocks were distributed widely in the strata of the late Paleozoic Era and developed concentratively in the upper section of the (Lower) Carboniferous Series, the Upper Carboniferous Series and the Lower Permian Series. These (volcanic) rocks were interlayered with the normal sedimentary rocks in the same time. According to the study of the petrostratigraphy, occurrence of the volcanic rock beds and their types of contact, the (volcanism) has four cycles, and they contain nine rhythms of volcanic effusion. On the basis of studying the geological characteristics of the volcanic rocks, rock types, petrochemical and trace elements geochemical features in the study area, the authors discuss their evolution and formation environment.