Late Silurian–Early Devonian Magmatism in the Southeastern Sarysu–Teniz Uplift, Central Kazakhstan: Zircon U–Pb Geochronology and Major-Element Geochemistry

The southeastern Sarysu–Teniz Uplift in Central Kazakhstan is partly concealed beneath Cenozoic sediments, which complicates the correlation and age assignment of its Paleozoic magmatic rocks. This study combines new zircon U–Pb ages from four felsic volcanic samples with whole-rock major-element data for volcanic and intrusive rocks to constrain the timing of magmatism and assess their compositional relationships. The principal zircon populations yield concordia ages of 414 ± 3, 415 ± 2, 421 ± 2, and 414 ± 2 Ma, with uncertainties reported at 2σ, indicating Late Silurian–Early Devonian magmatism. Older populations at 440 ± 6 and 438 ± 6 Ma and a single ca. 2.67 Ga zircon document older components, although their provenance remains unresolved. Comparison with previously published intrusive ages supports partial temporal overlap between volcanic and plutonic activity, but does not establish a single magmatic system. Major-element variations are compatible with differentiation involving fractional crystallization, while crustal melting, assimilation, magma mixing, and source heterogeneity remain possible contributors. The available geochemical data do not uniquely identify source lithologies or tectonic setting. These results refine the chronology of the sampled volcanic rocks and provide a basis for revising their regional correlation and relationship with intrusive magmatism.