High-precision U-Pb geochronology of high-Ti basalts: investigating the duration of magmatism in the Paraná Magmatic Province

Abstract

The magmatic activity of Large Igneous Provinces (LIPs) can trigger climatic and environmental disturbances, and in some cases, cause mass extinction events. The interaction of subvolcanic rocks (sills and dyke swarms) with volatile-rich sedimentary host rocks during LIP emplacement can enhance the release of greenhouse gases and thermogenic volatiles, potentially resulting in oceanic anoxic events. In the Paraná Magmatic Province (PMP), thick tholeiitic basalt lava flows prevail, in addition to subvolcanic mafic rocks (sills and dykes) intrusive in pre-volcanic sediments of the Paraná Basin. The age of basaltic magmatism in the PMP is still highly debated and is mainly based on 40Ar-39Ar data with larger uncertainties which overlap with the Valanginian oceanic anoxic event. This work aims to obtain high-precision U-Pb ages of basic magmatism, predominant in the Paraná Magmatic Province, in high-Ti intrusive and extrusive mafic rocks (Pitanga type) of the PMP, including the Limeira Sill and phaneritic basalts, to evaluate the possible correlation of PMP mafic magmatism with the Valanginian Event.