This paper presents first UPb detrital zircon ages, major and trace element geochemical data and whole-rock Nd and Hf-in-zircon isotope data from sandstones of the Char and Zharma zones of eastern Kazakhstan. Petrographically the sandstones represent greywackes. The UPb ages of detrital zircons show unimodal distributions peaked at 345340 and 330325яMa indicating post-Early Carboniferous deposition. The sandstones have high CIA values (6068), suggesting moderate to weak chemical weathering. Their high ICV values (1.11.3) and relatively high MgO and low Y, Nb indicate an immature probably maficintermediate igneous source (low La/Th, medium Hf). Positive whole-rock Nd(t) and zircon Hf(t) indicate dominantly juvenile character of igneous rocks in the provenance. In total, the unimodal character of UPb detrital zircon age patterns, the chemical composition of sandstones similar to that of associated volcanic rocks and the positive values of Nd(t) and Hf(t) suggest their derivation from one or more intra-oceanic arcs. The data from eastern Kazakhstan fit those obtained from late Paleozoic greywacke sandstones of NW China. The new geochemical and geochronological data from sandstones and published data from oceanic and supra-subduction ophiolites of eastern Kazakhstan suggest an extended Pacific-type subduction system in the western Paleo-Asian Ocean in Devonianearly Carboniferous time.