TRANS-CRUSTAL MAGMATIC CONTROLS ON ZIRCON TI CONTENTS IN PORPHYRY CU-FORMING MAGMAS: EXAMPLES FROM SONORA AND CHILE
Recent work has proposed that low, homogeneous Ti concentrations in zircon serve as a proxy for “super-wet” (>6 wt% H₂O) arc magmatism, which is considered essential for the generation of porphyry Cu-forming magmas. Using coupled thermodynamic and trace-element modeling, we test how sensitive zircon Ti content is to parental melt composition and Zr content. Our results indicate that zircon Ti content is sensitive to melt composition and inherited Zr at a magnitude comparable to that of water content itself. We frame these results within a trans-crustal context, where residence time and crustal architecture jointly influence water enrichment and Zr inheritance during magma differentiation. Preliminary comparison with independent geochemical datasets from different arc settings (Sonora and Chile) supports this architecture-dependent variability. These findings suggest that zircon Ti content should not be considered a single proxy for super-wet magmatism, but rather an indicator of the broader trans-crustal magmatic evolution. Our study further cautions against using zircon Ti content as a proxy for super-wet magmas and, ultimately, porphyry Cu-forming magmas in exploration contexts.