新疆北部晚石炭世沉积建造特征

新疆北部晚石炭世沉积建造类型复杂,有七大类十亚类,呈东西或近东西向条带状展布(长宽比值为3—25),岩石类型复杂多变,微量元素分配状态为不规则型,分选性差,稳定性小,海相为主,岩相古地理变异极快,厚度巨大,厚度变化率为2—20％,沉积中心明显且呈带状或串珠状分布、迁移迅速,富含火山物质,属地槽型沉积建造。晚石炭世新疆北部可分为北部优地槽型、南部渺地槽型两大类型建造区,前者自北而南又可以分出四个亚建造区,即布(布尔律)—富(富蕴)区、乌(乌尔禾)—克(克拉玛依)区、温(温泉)—双(双井子)区、特(特克斯)—哈(哈密)区。上述特点的产生受新疆北部晚石炭世古海西地槽区发展演化的控制。

CHARACTERISTICS OF SEDIMENTARY FORMATION OF LATE CARBONIFEROUS AGE IN NORTHERN XINJIANG

Sedimentary formations of Late Carboniferous age in northern Xinjiang are complex. There are seven types and ten subtypes. They are distributed in E-W or approximately E-W direction, and the ratio of length to width is 3-25. Rock types within them arc complex and variable. The state of distribution of microelements belongs to irregular type. The sorting and stability are low and washing is weak. They arc mainly marine in facies and lithologic facies and palaeogeographic variation are very rapid. The thickness is huge and the rate of variation in thickness is 2-20%. The centers of sedimentation are clear, distributed in a belt or a rosary and migrated frqeuently. The sedimentary formations contain rich volcanic materials and belong to geosyncline-type sedimentary formations.Northern Xinjiang may be divided into two sedimentary formation regions, i.e. eugeosyncline-type region and miogeosyncline-type region. The former may be further divided, from north to south, into four subregions, i.e.Bnerjin-Fuynn subregion, Urho-Karamay subregion, Wenquan-Shangjinzi subregion and Tekes- Hami subregion. The characteristics mentioned above are controlled by the development and evolution of the northern Xinjiang Hercynian geosyncline region of Late Carboniferous age.