新疆阿克苏地区新元古代晚期地层沉积相及层序地层研究

Study on the Late Proterozoic sedimentary facies and sequence stratigraphy in Aksu area,Xinjiang

通过阿克苏地区尤尔美那克村、尤尔美那克村西、阿克苏水泥厂实测剖面研究,将该地区南华系晚期和震旦系地层由下向上划分为:冰成相、浅海陆棚相、潮坪相、滨岸相、浅海相以及碳酸盐台地相。这些地层可分为两个层序(Sq1和Sq2),Sq1层序由尤尔美那克组地层和苏盖特布拉克组下亚组组成,包括冰成相、浅海陆棚相、潮坪相和滨岸相,属典型的冰期地层层序。Sq2层序由苏盖特布拉克组上亚组和奇格布拉克组组成,包括滨岸相,浅海相和碳酸盐台地相,属于潮汐作用为主的滨浅海碎屑岩-碳酸盐岩层序。根据年龄、碳同位素和冰期沉积特征综合对比,阿克苏地区晚元古代Sq1和Sq2层序应分别对比于鲁克塔格地区的第4和第5层序,说明尤尔美那克冰期相当于特瑞艾肯冰期,并揭示阿克苏地区在晚元古代早期应有较长阶段的缺失或剥蚀。

According to the research of the stratigraphic sections in Yuermeinak Village,west of Yuermeinak Village and Aksu cement plant areas,six sedimentary facies have been recognized including glacigenic,shelf,tidal flat,littoral,neritic and carbonate plateau facies. Two sedimentary sequences are identified as Sq1 and Sq2. The Sq1 consists of Yuermeinak Formation and the lower part of the Sugetbrak Formation which represented a typical ice age sedimentray sequences,containing glacigenic,shelf,tidal flat and littoral facies. The Sq2 consists of the upper part of Sugetbrak Formation and Chigebrak Formation,containing littoral,neritic and carbonate plateau facies,representing an offshore and shallow sea detrital-carbonate sequence. The correlation of ages,carbon isotopic data and glaciation sedimentary characteristics indicates that the Sq1 and Sq2 in Aksu area could be well correlated with the fourth and fifth sequences in Quruqtagh area,which illustrates that the Yuermeinak glaciation was corresponded with Tereeken glaciation and reveals that the Aksu area experienced absence or erode during Early Neoproterozoic era.