Constraining crustal-level granite emplacement through thermobarometry and gravity modelling: Insights from the Ediacaran Acari Batholith, Borborema Province, NE Brazil

• Two magmatic roots were identified, each associated with distinct granite facies. • Bodies separated at surface revealed as one magmatic system by gravity modelling. • Granite emplacement at mid-crustal depths (∼10–13 km) reflects Seridó Group burial. • Host rock metamorphism intensifies toward the magmatic feeder zones. • A migmatite-dome system is interpreted as the magma source for the Acari Batholith. The Acari Batholith is a syntectonic Ediacaran (∼575 Ma) intrusion emplaced in the Seridó Belt, northeastern Brazil, during the Brasiliano Orogeny, a major tectonic event associated with the assembly of West Gondwana. It represents the largest granitic body within the belt. While the exposed geology of the Acari Batholith is well characterized, its subsurface geometry remains poorly constrained. To address this, we performed 2.5D forward gravity modelling to investigate its architecture and integrated the results with existing AMS, thermobarometric, borehole, and regional data. The modelling results represent one plausible subsurface configuration that is consistent with the gravity data and available geological constraints. They reveal an eastward-shifted feeder zone with two NE-SW aligned roots. The model suggests a predominantly shallow body, with a low-angle floor. A thin mica schist layer overlies the northern root and separates the Acari Batholith from the Acauã Stock, a satellite body that belongs to the same magmatic system. Thermobarometric estimates based on the normative quartz–orthoclase–albite geobarometer yield crystallization pressures of 2.6–3.5 kbar, consistent with the HT/LP metamorphism in the Seridó Belt. Synchronicity between magma emplacement and Brasiliano deformation is inferred from the alignment of internal magmatic fabrics with regional structures, while a mylonitic zone along its western margin developed after solidification. Cordierite + sillimanite assemblages in adjacent mica schist further attest to high temperatures near the roots. Combined with regional data, these results support the interpretation that the Acari Batholith represents a magmatic expression of the migmatitic dome system formed during Brasiliano transpression.