摘要
库车再生前陆盆地冲断构造楔由一系列向南运动的逆冲断层和相关褶皱组成。冲断楔的北部以断层转折褶皱、断层传播褶皱、双重逆冲构造为主。断层楔的前缘发育了很好的滑脱膝折背斜 ,全为肓断层控制 ,形成隐蔽式前锋。冲断层的就位从中新世开始 ,自北向南迁移 ,前锋的构造形成在第四纪。造成逆冲断层的地壳水平缩短作用速度在中新世较慢 ,平均为 0 .35 5mm/a ,上新世中期达 0 .82mm/a ,而到上新世晚期和第四纪速度增大了约一个数量级 ,达到 1.2 9～
Kuqa rejuvenation foreland basin and its thrust wedge of foreland deformation belts are structurally responsed to the India Eurasia collision in the interior of Asia continent. Based on the detailed surface geology reconnaissance and interpretations of many seismic profiles, we conclude that thrust wedge of deformation belt in Kuqa rejuvenation foreland basin is divided into five structural units, including the marginal thrust and hidden structural zone, the Shidike anticline zone, the North linear anticline zone, the Baicheng piggy back depression and the Qiulitage thrust frontal zone. The fault related folds are the basic deformation styles of the rejuvenation foreland thrust wedge, which are classified into nine kinds of fault related folds, including fault bend fold, fault propagation fold, detachment kink fold, duplex, pop up, hybrid fault bend/detachment fold, stacked anticline, composed wedge structure and superimposed fault bend/fault propagation fold. In the northern part of the flat/ramp thrust wedge, the fault related folds are mainly of fault bend folds, fault propagation folds, and duplexes. For the very front of the wedge there exist well developed blind thrusts and detachment kink folds, forming a typically cryptic thrust wedge front edge. Growth strata recorded accurately initial emplacement ages of every structure belt and detailed forming processes. Thrusts and thrust related folds propagate from the north to the south within the thrust wedge, i. e. Misibulake anticline initiated in the Miocene (23.3Ma), velocity of blind thrust 0.16mm/a ; Kalabahe anticline and Kelasu anticline in 16.9Ma, velocity of hidden thrust 0.16mm/a and 0.16mm/a; Dawanqi anticline in 3.6Ma, velocity of hidden thrust 0.82mm/a; Dongqiulitage anticline in 3Ma, velocity of blind thrust 1.3mm/a; and Yaken anticline in 1.87Ma, velocity of hidden thrust 3mm/a. The crustal shortening velocity which caused the thrusting is slow at about 0.355mm/a in average in the Miocene, then approaches 0.82mm/a in middle Pliocene. During the late Pliocene and the Quaternary the velocity gets faster in about one magnitude order, up to 1.29-3mm/a, implicating that an accelerating crustal shorting process occurred in the late Cenozoic in the Kuqa thrust belt and approached a climax in the Pliocene and the Pleistocene.
出处
《高校地质学报》
CAS
CSCD
2001年第3期257-271,共15页
Geological Journal of China Universities
基金
"九五"国家自然科学基金重点项目 (批准号 49832 0 40 )
"九五"国家重点科技攻关项目 (96 - 111- 0 1- 0 1- 0 4)资助
关键词
库车再生前陆盆地
冲断构造楔
新生代构造
逆冲断层相关褶皱
背斜前翼生长三角
地壳缩短速度
thrust wedge of Kuqa rejuvenation foreland basin
Cenozoic structures
thrust related fold
growth triangle of front limb of anticline
crustal shortening velocity
