The northern Sichuan Basin of central China is an important region for investigating the continent-continent convergence that resulted from the closure of the Palaeo-Tethys Ocean. The Early-Middle Jurassic sediments of this basin record the palaeogeography, palaeoenvironments and tectonic evolution of the southern Qinling orogenic belt, especially the Dabashan thrust belt. Detailed sedimentological investigations, coupled with provenance analyses using zircon UPb geochronology, demonstrate that during Early Jurassic times, conglomerate megafan facies extended across the northern Sichuan Basin into the Micangshan area deformed by South Dabashan thrusting and reached even as far as the Mianlue suture belt. These megafan deposits were mainly reworked from the Silurian sediments of the North Dabashan thrust belt (also called the South Qinling orogenic belt), north of the Mianlue suture. These conglomerates record the initial thrust-driven uplift and exhumation of the Qinling orogenic belt that rapidly followed the diachronous closure of the Mianlue oceanic basin. Moreover, our results show that the detrital materials of meandering stream, lacustrine and braided river delta facies that accumulated in the Middle Jurassic mainly originated from the southern Qinling orogenic belt, Mianlue suture zone and northern South China block, suggesting the southward progradation of the Dabashan fold-thrust belt onto the northern Yangtze block and the southward migration of the basin centre. These findings support a model in which the Early to Middle Jurassic evolution of the northern Sichuan Basin may have been triggered by East Asian convergence.

四川盆地北部是研究古特提斯洋闭合引起的陆陆汇聚的重要区域。该盆地早中侏罗世沉积物记录了南秦岭造山带特别是大巴山冲断带的古地理、古环境和构造演化。详细的沉积学调查，加上使用锆石 U Pb 地质年代学进行的物源分析，表明早侏罗世砾岩巨扇相横贯川北地区，进入南大巴山逆冲变形的米仓山地区，直至勉略缝合带。这些巨型扇沉积物主要是由勉略缝合带以北的北大巴山冲断带（也称南秦岭造山带）的志留纪沉积物改造而成。这些砾岩记录了勉略洋盆历时闭合后秦岭造山带最初的逆冲驱动抬升和折返。此外，我们的研究结果表明，中侏罗世沉积的曲流河、湖泊和辫状河三角洲相碎屑物质主要起源于南秦岭造山带、勉略缝合带和华南地块北部，表明大巴山褶皱逆冲带向南进积到扬子地块北部，盆地中心向南迁移。这些发现支持了一个模型，即川北早侏罗世到中侏罗世的演化可能是由东亚汇聚引发的。