Potencial teórico de armazenamento geológico de CO2 nas rochas basálticas da região geográfica intermediária de Cascavel, Paraná

Abstract

The increase in anthropogenic carbon dioxide emissions has intensified global climate change, requiring mitigation strategies such as geological CO₂ storage. Basaltic rocks, due to their composition rich in divalent cations (Ca²⁺, Mg²⁺, Fe²⁺), have high potential for mineral carbonation of CO₂, converting it into stable carbonates. Ninety-four geochemical samples obtained from bibliographic sources were analyzed, delimiting the Intermediate Geographic Region of Cascavel as the study area. This is an exploratory analysis, conducted on a regional scale based on secondary geochemical data. To calculate the theoretical storage capacity, the methods of Renforth (2012), Zhang et al. (2023), Oliveira; Zuquette (2025), and a proposed adaptation that, like the method of Oliveira; Zuquette (2025), incorporated the Loss on Ignition (LOI) parameter into the equation of Zhang et al. (2023). The equations were standardized to provide results in KgCO2/m3 and consider the average densities of the different structural zones of the basalt. The results showed that the massive zones of the basaltic flows had the highest median storage capacities in all methods. The incorporation of the LOI parameter reflected compositional variation and possibly the presence of secondary minerals, indirectly affecting reactivity and increasing the dispersion of results. Although massive zones showed slightly higher capacity, there is a hypothesis that basalts classified as massive may contain microamygdules filled with clay minerals (indicated by LOI), which would favor greater reactivity and, consequently, higher estimates of storage potential. The analysis of greenhouse gas emissions in the same region based on SEEG data from 2023 highlighted Cascavel, Toledo, and Foz do Iguaçu as the main emitters, with emphasis on the energy sector. Additionally, by evaluating the municipalities with the highest normalized emission values, areas with higher proportional CO₂e intensity were identified, especially associated with agriculture and livestock, which complements the understanding of spatial emission patterns in the Intermediate Geographic Region of Cascavel. It is concluded that the studied region, aligning high emission demand with the availability of geological CO₂ sinks in its extensive basalt formations, presents favorable conditions for the implementation of Carbon Capture and Storage projects. However, complementary studies on a real scale for validation are recommended.