Proximal sedimentary system in foothill belt of foreland basin has become a hot and hard topic in sedimentology in recent years.During the Jurassic depositional period

a set of proximalcoarse-grained sedimentary systemwas developed in the foothill belt of Longmen Mountain in the western Sichuan Basin.We analyzed the provenance features and sedimentary system evolution in different periods using an integrated dataset of seismic

well logging

core and outcrop data.The results show that:(1) during the Jurassic

there were 5 provenances in the minor axis and near-major axis directions in the foothill belt of Longmen Mountain; (2) in the Early Jurassic

alluvial fan-meandering river delta-shore-shallow lake-semi-deep lake system dominated this area

while in the Middle and Late Jurassic

alluvial fan-braided river delta-shore-shallow lake system were developed well here; (3) three types of sedimentary models can be identified in the foothill belt of Longmen Mountain

namely the Early

Middle

and Late Jurassic sedimentary models.This study canprovide theoretical guidance and data support for the exploration of the tight sand gas reservoirs in the foothill belt of Longmen Mountain

and deepen our understanding of the proximal coarse-grained alluvial reservoirs.