Ferroan granitoid intrusions are rare in the Archaean rock record, but have played a large role in the evolution of the Proterozoic crust, particular in relation to anorthosite-mangerite-charnockite-granite suites. Here we discuss the petrogenesis of the ca. 2785–2805 Ma ferroan Ilivertalik Intrusive Complex, which has many geochemical similarities to Proterozoic iron rich granitoids. We present major and trace element whole rock chemistry and combined in-situ zircon U-Pb, Hf and O isotope data. The intrusive complex divides into: (i) minor tabular units of mainly diorite-tonalite compositions, which are typically situated along contacts to the host basement and (ii) interior larger, bodies of mainly granite-granodiorite composition. Geochemically these two unites display continuous to semi-continuous trends in Haker-diagrams. Whole rock REE enrichment display increases from Yb to La, from 10–25 to 80–100 times chondrite, respectively. The diorite-tonalite samples are generally more enriched in REE compared to the granite-granodiorite samples. The complex has hafnium isotope compositions from around +1.5 to −2.5 epsilon units and δ¹⁸O compositions in the range of 6.3 to 6.6‰. The complex is interpreted to be derived from partial melting in a crustal source region during anomalously high crustal temperatures.

Titanite is widely used in geochronology and petrogenetic studies, yet its behaviour during fluid-mediated alteration remains insufficiently constrained. This study investigates titanite alteration and element redistribution in the Mesoproterozoic Kabeliai granitoids (southern Lithuania) to evaluate their response to magmatic and hydrothermal processes. Petrography, EPMA, LA-ICP-MS, U-Pb geochronology, and mass balance modeling were combined to characterise titanite textures, chemistry, and isotopic evolution. Three titanite types were distinguished. Type 1 titanite preserves magmatic compositions and yields U-Pb ages of 1508 ± 19 (MSWD = 0.91; 2σ) and 1527 ± 9 Ma (MSWD = 0.54; 2σ), consistent with late magmatic crystallisation. Type 2 titanite represents a transitional fluid-altered stage, characterised by a porous texture. Type 3 titanite is interpreted to record hydrothermal recrystallisation, trace element depletion (Y, REE, Nb, Zr), and U-Pb resetting, with ages of 1454 ± 14 Ma (MSWD = 0.48; 2σ) and 1475 ± 23 Ma (MSWD = 0.63; 2σ) partially overlapping molybdenite mineralisation at ca. 1486 Ma. Mass balance modeling indicates that alteration was dominated by coupled albitisation and chloritisation, and by the redistribution of Ca, Si, and REE. In contrast, Ti remained relatively immobile at the rock scale and was locally redistributed among secondary phases via dissolution–reprecipitation. These results suggest that different titanite domains may preserve distinct stages of magmatic and hydrothermal evolution and highlight the importance of microstructural context when interpreting U-Pb ages in altered granitoid systems.