<p>This study investigates Zirconium (Zr) content variations and their genetic implications in Early Cretaceous A-type granites from the Gan-Hang Belt, southeastern China, and aims to elucidate how Zr traces continental crustal evolution. Through systematic analyses of geochronological, geochemical, and isotopic data, these rocks can be classified into low-Zr and high-Zr magma systems; the high-Zr magma system includs the Caiyuan monzoporphyry, Honggong quartz syenite, and Dazhou rhyolite. High-Zr magma system shows coherent major-element trends: TiO₂, Al₂O₃, FeO^T, MgO + Fe₂O₃, CaO, and P₂O₅ decrease as increasing SiO₂. Trace elements reveal declining Ba, Sr, Eu/Eu^*, La/Yb, and Sr/Y with rising Rb/Sr. The samples are characterized by LREE enrichment, HREE depletion, and negative Eu anomalies, along with enrichments in Rb, Th, U, Nb, Ta, Zr, but Hf and depletions in Ba, Sr, Eu, and Ti. Isotopically, Isotopic data (<i>ε</i>_Nd(<i>t</i>) = −8.3 to −5.5 and zircon <i>ε</i>_Hf(<i>t</i>) = −15.1 to +7.2) and two-stage Nd-Hf model ages overlap with regional A-type granites, which suggests a common source involving ancient crust mixed with mantle-derived mafic magmas. The key control on Zr enrichment is the thermal state of the magma system: high-temperature, high-flux mantle inputs induced Zr undersaturation, dissolution of early zircons, and Zr release into melts. Subsequent melt segregation transported Zr-enriched liquids to shallow crustal levels, providing key insights into Zr behavior during crustal differentiation and crust-mantle interaction.</p> Graphical Abstract <p></p>