Physical Modeling of the Influence of Basement Slope on the Formation and Evolution of Salt-related Fold-and-thrust Structures in the Overburden:Taking the Misikantake Anticline in the Western Kuqa Depression as an Example
To study the influence of the subsalt basement slope on the formation and evolution of salt overburden in the salt sedimentary fold-thrust belt in the western Kuqa Depression,such as the Miskantake anticline,two sets of compressional sandbox models were set up based on the interpreted results of seismic profiles in the study area.The experimental results show that:(1)In salt-bearing sedimentary basins,differential salt-related structures occur in the overburden due to differential topographic relief in the subsalt basement under lateral compression stress.When the topographic relief in the subsalt basement is relatively flat,symmetrical detachment folds(salt-related folds)are prone to develop in the salt overburden;when pre-existing slopes occur in the subsalt basement,asymmetrical detachment folds(salt-related folds)are prone to develop in the salt overburden.(2)The pre-existing basement slope has a blocking effect on the lateral flow of salt rock during the shortening.The vertical accumulation and thickening of salt rock on the basement slope resulted from the strengthened folding of the salt overburden,leading to the development of asymmetric salt-related folds and accommodative thrust faults in the limbs of these detachment folds.Therefore,based on the experimental results,the characteristics of topographic relief in the subsalt basement,and the horizontal and sectional structural characteristics of the Miskantake anticline,it is inferred that the pre-existing slope in the subsalt basement played an important role in the structural deformation and evolution of the salt overburden,and the formation and evolution of the Misikantake anticline in the study area.
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