/// The uppermost tectonic feature of the northwestern margin of place w:st="on">Junggar Basinplace> is a group of thrusts there. Disputes over these thrust structures are mainly about their formation time and attributes, and the relevant debate of whether the place w:st="on">Junggar Basinplace> is a faulted depression or a foreland basin. At the northwestern margin, granite and dyke swarms developed, suggesting that the studied area underwent an extension from 314 Ma to 255 Ma. The facts that the sedimentary scope of Jurassic is wider than that of Triassic and the alkali basalt developed in the Early Jurassic indicate that the place w:st="on">Junggar Basinplace> underwent an extension and kept expansion in Jurassic. The Late Triassic strata unconformably overlying the granite indicates that the formation time of these thrust structures might be from the late Permian to the early Triassic, no later than the Late Triassic. Based on the analysis above, the authors believe that the thrust structures are short term inversion structures occurring between 314~255 Ma extension and Jurassic extension, rather than large scale thrust belts associated with orogeny.
