Recognition of Gold Mineralization Favorability Zones Through Airborne Gamma-Ray Spectrometry and Magnetometry in Brusque and BotuverだRegion, Southern Brazil

Abstract

ABSTRACT. The northeastern portion of Santa Catarina State, southern Brazil, bears important primary gold mineralization associated with granitic intrusions with potassic and phyllic hydrothermal alteration zones and a phase shear zone reactivation. Airborne radiometric and magnetic data were applied in the study area through the use of gamma-ray spectrometry (Total Count, K, eTh and eU) and suggestive parameters of hydrothermal alteration as Kd, Ud and F, in association with geological units, while magnetometry (RTP, THDR, TDR and Signum Transform) was applied in the definition of the structural framework. Geophysical data was interpreted and integrated to geological information, such as lithologic units, structures, shear zones and gold mineralization, using the knowledge driven and index overlay methods in order to define favorable targets. The geophysical and geological data exhibit good correlation, as seen in the gamma-ray spectrometric domains and magnetic lineaments, and the favorability map shows important target areas for primary gold mineralization. It was possible to observe in the geophysical maps that shear zones and faults have more influence in the occurrences than potassic and phyllic hydrothermal alteration related to granitic intrusions.Keywords: geophysical exploration, knowledge-driven, Dom Feliciano Belt.RESUMO. A porção nordeste do estado de Santa Catarina, sul do Brasil, possui importantes mineralizações auríferas primárias associadas a intrusões graníticas com zonas de alteração hidrotermal potássica e fílica e posterior fase de reativação de zonas de cisalhamento. Dados radiométricos e magnéticos aerogeofísicos foram aplicados na área de estudo através do uso de gamaespectrometria (Contagem Total, K, eTh e eU) e parâmetros sugestivos de alteração hidrotermal como Kd, Ud e Parâmetro F. Em associação com unidades geológicas, enquanto a magnetometria (RTP, GHT, ISA e Signum Transform) foi aplicada na definição do arcabouço estrutural. Os dados geofísicos foram interpretados e integrados às informações geológicas, como unidades litológicas, estruturas, zonas de cisalhamento e mineralizações de ouro, utilizando os métodos knowledge-driven e index overlay para definir alvos favoráveis. Os dados geofísicos e geológicos apresentam boa correlação, como visto nos domínios espectrométricos de raios gama e lineamentos magnéticos, e o mapa de favorabilidade mostra áreas-alvo importantes para a mineralização de ouro primária. Foi possível observar nos mapas geofísicos que as zonas de cisalhamento e as falhas têm mais influência nas ocorrências do que as zonas de alteração hidrotermal potássica e fílica relacionada às intrusões graníticas.Palavras-chave: exploração geofísica, knowledge-driven, Cinturão Dom Feliciano.

Insights into tectonic reactivation and landscape development processes at the Paraná Basin border using integrated geomorphometric and radiometric analyses

“…The results indicate that data produced from the integrated analysis of different datasets generated from various processes allow a more cohesive interpretation of established correlations. Pereira and Ferreira (2018) also discussed the correlation between the K d and F-Parameter and identified areas favorable to hydrothermal mineralization. The analysis confirmed high favorability in areas where the K d and F-Parameter correlation is high.…”

“…The F-Parameter (Gnojek and Prichystal 1985, Barbuena et al 2013, Pereira and Ferreira 2018 derives from the contribution of potassium and uranium/thorium ratio. This procedure allows identifying different geological scenarios since relatively higher values correspond to areas with chemically altered rocks, whereas relatively lower values indicate areas with weathering of K-bearing minerals.…”

Uso de dados aeromagnéticos e eletromagnéticos na avaliação de estruturas condicionadoras de aquíferos fraturados e produtividade dos poços, no Sistema Aquífero Embasamento Cristalino, na região de Bagé (RS)

“…Os métodos de realce gerados foram Amplitude do Sinal Analítico (ASA) e Derivada Vertical (GZ), a partir do mapa de anomalias magnéticas de Redução ao Polo Continuado para Cima 500 metros. Os lineamentos foram interpretados seguindo a metodologia tradicional (FERREIRA et al, 2010;CASTRO, 2014;PEREIRA;, onde são marcados os lineamentos correspondentes aos maiores valores magnéticos.…”

Modification of Radiogenic Heat Production (RHP) Equation due to Radioactive Disequilibrium in Rock Samples from Gamma-Ray Spectrometry

“…The method can be applied to evaluate concentrations of radionuclide in many geothermal fields and excavation sites (Faruwa et al 2020;Cinelli et al 2020). It can also be used to decide the nature and uranium migration (UM) rate in many crustal formations (Youssef et al, 2017;Pereira and Ferreira, 2018;Reis et al 2020) (Yuan 2023), sedimentary surface identification for exploration of oil and gas, radioactive pollution discovery (Cinar et al 2017), mineral probing (Chandrasekaran et al 2014), pure earth science discoveries (Ray 2008;Sims 2021), facture and fissure unearthing linked with uranium concentrations elevation which is caused by uranium movement in fluid in the subsurface (Grozeva 2022) which can cause substantial problem for gamma-ray spectrometry investigation and explanation known as disequilibrium (Lefebvre 2022;Grozeva 2022;Cai 2015).…”