中生代鄂尔多斯盆地陆源碎屑成分及其构造属性

运用区域沉积-构造背景分析与陆源碎屑成分判别构造环境相结合的综合研究方法，在对鄂尔多斯盆地沉积-构造特征及其演化历史研究的基础上，采用Dickinson等陆源碎屑成分与构造环境关系判别标准和图版，统计分析了鄂尔多斯盆地中生代陆源碎屑成分特征及其与盆地构造属性的关系。结果表明，中生代鄂尔多斯盆地具有前陆盆地的性质，但又不同于典型的前陆盆地，称之为类前陆盆地似乎更能反映盆地的实际。

Terrigenous Clastic Composition and Its Tectonic Feature in the Mesozoic of the Ordos Basin

The relationship between clastic composition and tectonic setting has provided a useful method to recognize the link of sedimentology and tectonic type.Based on the systematic analysis of regional sedimentary-tectonic character and clastic composition to determine the basin tectonic type of the Mesozoic in the Ordos Basin,it could be concluded as follows: First,there was a sinistral sheared stress field in mechanical property of the North China craton during the Mesozoic.There formed two major tectonic elements under the deformation of the stress field.One is the large uplifted zone in the east,and the other is the Ordos Basin in the west.Simultaneously,the west edge thrust belt of the basin was formed.The main structure of the Mesozoic in the Ordos Basin was presented as“deep depression in the west-slope and forebulge in the east”.Also,there were a large amount of conglomerate-clastic rocks of the Upper Triassic, the Upper Jurassic,and the Lower Cretaceous in the deep depression.These sedimentary tectonic charactes showed that the Mesozoic of the Ordos Basin is most likely to be a quasi-foreland basin. Meanwhile,the subsidence center of the Mesozoic in the Ordos Basin could not coincide with the sedimentary center,These two centers were not only changable but also located at different positions.From the late Triassic to the Early Cretaceous,the subsidence center of the west depression migrated along the thrust orientation,and the sedimentary center in the middle part of the basin circled anti-clockwisely.Obviously,It was the result of the west edge thrust belt of the basin and the sinistral sheared stress deformation of the North China craton during the Mesozoic. Futhermore,most of the Mesozoic samples fall in the Recycled Orogen Provenances in the QFL and QFLT triangular diagram delinested by Dickinson(1979),It is suggested that the clastic resources of the fills in the Mesozoic be like that of the foreland basin.However,the most chemical component ratios of the Mesozoic samples are not of the typical foreland basin character,but similar to the quasi-foreland basin.For example,Fe₂O₃+MgO=4%～6%,TiO₂=0.3%～0.5%，K₂O/Na₂O=0.8%～1.7%,Fe₂O₃/K₂O=1.1%～1.9% and SiO₂/Al₂O₃=5.5%～8.9%. Therefore,the Mesozoic Ordos Basin was not a typiocal foreland basin,but a quasi-foreland one .It was the most result of the west edge therust belt of the basin during the Meszozic, especially during the late Triassic,the late Jurassic and the Early Cretaceous.