Abstract: Early Paleozoic stratigraphic sequences are well exposed in the North Altyn ophiolitic mélange zone and its adjacent Central Altyn block, which documented the subduction and collision of the North Altyn Ocean. The Ordovician sequence within the North Altyn ophiolitic mélange zone is composed of clastic rocks, volcanic rocks and carbonates. Detrital zircon grains from the volcaniclastic sandstone samples determine a single age population at 420～440 Ma (peak at 470 Ma), with a maximum depositional age (YPP) of 456 Ma. Moreover, the detrital grains were predominantly derived from a juvenile crustal source (7.4＞ε_Hf(t)＞0). Coeval Ordovician Elantage Formation exposed in the northern margin of the Central Altyn block also displays a single age population, but at 510～450 Ma (peak at 470～465 Ma), with a YPP of 446 Ma. However, their Hf isotopes (−1.8～−8.4) indicate a source region dominated by crustal recycling. The zircon trace element signatures of both units argue for derivation from a granitic source. Field geology, detrital zircon age distribution patterns, along with zircon isotopic and geochemical compositions, suggest deposition in an active plate margin setting. This, together with regional geology and previous studies, favors the Elantage Formation as deposited in an Early Ordovician retro-continental arc basin related to the south directed subduction of the North Altyn Ocean, with detritus derived from the Cambrian-Ordovician continental margin arc type granitoids in the northern Central Altyn block. In contrast, the Ordovician sequence within the North Altyn ophiolitic mélange zone may have been deposited in a younger fore-arc basin, subsequent to retreat of oceanic subduction and the extension of the continental central Altyn block. The identified Ordovician continental arc margin basins argue for continuous subduction of the North Altyn Ocean from the Cambrian to the Ordovician period, which closed in late Ordovician.