库车前陆盆地东秋里塔格构造带构造分段特征

STRUCTURAL SEGMENTATION OF THE EASTERN QIULITAGE STRUCTURAL BELT IN KUQA FORELAND BASIN,XINJIANG

通过对研究区内不同位置的5条典型地震剖面解释,发现DQ94-226测线以西的盐上地层主要发育南倾被动顶板反冲断裂,盐层发育盐枕构造和盐推覆构造,盐下地层发育断层相关褶皱和逆冲断裂带;DQ94-226测线以东的盐上地层发育向南逆冲的大型断裂,盐层发育盐推覆构造,盐下地层主要发育断层相关褶皱和突起构造(pop-up)。平衡剖面分析表明,东西两段的南北向构造缩短量具有较大的差异性,西段的构造缩短明显大于东段。沉降史分析表明自东向西,构造活动的幅度依次增大,西段的构造活动明显比东段强烈。由此认为东秋里塔格构造带可以分为东西两段,即西段的库车塔吾构造带和东段的迪那构造带。

It was found from 5 typical seismic sections in the Qiulitage structural belt that the studied area can be divided by the DQ94-226 seismic line into 2 distinct parts with different structural types. In the west part passive roof recoil fault was developed above the salt layer, salt pillow and salt nappe were developed in the salt layer, and fault-related fold and thrust belt were developed below the salt layer. In the east part reverse fault thrusting southward was developed above the salt layer, salt nappe was developed in the salt layer, and fault-related fold and popup structure were developed below the salt layer. Analysis of the balanced section shows that the shortening amount is quite different between the west and the east, as the shortening amount for the west part is more than that for the east part. Analysis of the subsidence history shows that the tectonic movement becomes more and more intensive from east toward west, since the tectonic movement in the west appears to be more intensive than in the east. Therefore the eastern Qiulitage structural belt can be divided into two segments： Kuqatawu structural belt in the west and Dina structural belt in the east.