The Linxi Basin is situated at the eastern portion of the Tianshan-Solonker suture where the Paleo-Asian Ocean closed and represents the key region to understand the tectonic evolution of the Solonker suture. The Linxi Basin has the best preserved Permian sediments and its formation mechanism is much debated. Two controversial Permian tectonic backgrounds are proposed for this basin, i.e., oceanic-continental convergence (hence an arc basin related to subduction) versus post-orogenic extension (hence a crustal/lithospheric subsidence basin). Oceanic-continental convergence indicates subduction of oceanic lithosphere beneath the continental boundary of the North China Craton, whereas post-orogenic extension implies a thickened continental lithosphere experienced a drip-like gravitational instability. To address this controversy, we conduct subduction and drip (lithospheric instability) numerical experiments to calculate model predictions of surface topography for the Linxi Basin across the Solonker suture. Comparisons between the model predictions and the Permian sedimentary records in the Linxi Basin are made to determine which model can better explain the sedimentation. The persistent accumulation of Permian sediments indicates continuous crustal subsidence, which fits better the predicted subsidence from our drip model. By contrast, our modelled subduction-induced surface evolution in the Linxi Basin generally shows a switch from subsidence to uplift. The better fitting of the drip tectonics indicates that the post-orogenic extension rather than subduction tectonic setting would be more suitable to explain the Linxi Basin development during the Permian. In addition, the spatial and temporal distribution of magmatic activities is consistent with drip process. Our preferred Permian basin formation induced by drip model favors an early closure of the Paleo-Asian Ocean before the Permian.

林西盆地位于天山一索隆克缝合线的东部，古亚洲洋封闭了该地区，是了解索隆克缝合线构造演化的关键区域。林西盆地的二叠纪沉积物保存最完好，其形成机制尚有争议。对于该盆地，提出了两个有争议的二叠纪构造背景，即海洋-大陆辐合（因此与俯冲有关的弧形盆地）与造山运动后的扩张（因此使地壳/岩石圈沉降盆地）。海洋-大陆交汇表明华北克拉通大陆边界以下的海洋岩石圈被俯冲，而造山后的扩张意味着增厚的大陆岩石圈经历了点滴状的重力失稳。为了解决这个争议，我们进行俯冲和滴灌（岩石圈不稳定性）数值实验，以计算横跨Solonker缝线的临溪盆地表面地形的模型预测。将模型预测与临西盆地的二叠纪沉积记录进行比较，以确定哪种模型可以更好地解释沉积。二叠纪沉积物的持续堆积表明地壳持续沉降，这更适合我们的滴水模型预测的沉降。相比之下，我们对临溪盆地俯冲作用引起的地表演化的模拟通常显示出从沉降到隆升的转变。滴水构造的更好拟合表明，造山后的扩展而不是俯冲的构造背景将更适合于解释二叠纪期间的林西盆地发育。此外，岩浆活动的时空分布与滴水过程一致。我们首选的由滴水模型引起的二叠纪盆地形成有利于早于二叠纪封闭古亚洲洋。