The Shishuyuan Formation, located in the North Qinling Orogenic Belt, is a set of terrigenous clastic deep- water flysch deposits, composed mainly of slightly metamorphosed sandstone and mudstone. Its age assignment has historically relied on regional stratigraphic correlation and paleontological fossils collected from carbonate lenses within the sequence. However, chronological studies specifically targeting the terrigenous clastic rocks remain unstudied. LA- MC- ICPMS zircon U- Pb dating results show that the detrital zircon ages of the Shishuyuan Formation range from 438 to 3562 Ma, with a primary peak at ca. 949 Ma and five secondary peaks at ca. 2482 Ma, ca. 1707 Ma, ca. 1140 Ma, ca. 839 Ma and ca. 514 Ma. The youngest population of detrital zircon ages range from 438 to 543 Ma. Combined with the Devonian greenschist- facies metamorphism observed in the formation and the absence of ca. 414 Ma depositional records from the adjacent Kuanping Group to the north, the main depositional age of the Shishuyuan Formation is inferred to be the Middle—Late Silurian (438~415 Ma). Integrated regional studies suggest that the Shishuyuan Formation represents a tectonostratigraphic unit composed of sedimentary subunits of varying ages, which requires further subdivision into distinct units.Provenance analysis indicates that the sediments were primarily derived from the North Qinling Belt, with secondary contributions from the southern margin of the North China Block and the South Qinling Belt, characterized by a dual provenance. The tectonic setting of the Shishuyuan Formation and the Kuanping Group (Xiewan Formation) is inferred to represent a shared marine basin. However, unlike the late back- arc basin of the Erlangping Group, this basin is interpreted as a continental margin basin formed during Middle Silurian to Devonian post- collisional extension in the North Qinling Orogenic Belt.