Evolution of fluorite-mica-feldspar veins: Evidences of a fossil geothermal system in the são Gabriel terrane and consequences for Pb-Zn-Cu metallogeny

Hoerlle, Guilherme Sonntag; Remus, Marcus Vinicius Dorneles; Dani, Norberto; Gomes, Márcia Elisa Boscato; Ronchi, Luíz Henrique

doi:10.1016/j.jsames.2019.03.006

Cited by 8 publications

(4 citation statements)

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“…Sedimentary lithotypes and hydrothermal alteration increase susceptibility slightly. In this case, magnetometry could be used to delineate the geological structure that carried the hydrothermal fluids in the magmatic‐hydrothermal system (Hoerlle et al ., 2019; Remus et al., 2000). It can also be used to distinguish the types of hydrothermal alteration that destroyed the magnetite and resulted in a negative anomaly.…”

Section: Discussionmentioning

confidence: 99%

“…The genesis of the Santa Maria deposit is controversial, and three different hypotheses are considered: (1) distal volcanogenic (Biondi, 2015), (2) diagenetic (Veigel & Dardenne, 1990) and (3) magmatic‐hydrothermal (Hoerlle et al ., 2019; Remus et al., 2000). For this research, we adopted the magmatic‐hydrothermal genesis suggested by the results of the Pb–S geochemistry methodology in sulphides and U/Pb zircon SHRIMP.…”

Section: Regional Geologymentioning

confidence: 99%

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Petrophysics applied in mineralizations, hydrothermal alterations and lithology mapping: A case study from the Zn–Pb (Cu–Ag) epithermal deposit of Santa Maria, Brazil

Araújo

Silva

Barbosa

et al. 2022

Geophysical Prospecting

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The epithermal Zn–Pb (Cu–Ag) deposit of Santa Maria represents a distal magmatic‐hydrothermal system, whose mineralizations are controlled by fault systems located in the sedimentary units of the upper Camaquã Basin, above the tectonic units of the Sul‐Riograndense Shield. The hydrothermal alteration zones contain illite, chlorite and pyrite, besides galena, sphalerite, chalcopyrite and bornite. To improve the knowledge of this mineral system, this work investigated the petrophysical footprints of samples representing the predominant lithology, altered rocks and hydrothermal mineralization. The core samples of the predominant lithology, altered rocks and hydrothermal deposit mineralizations were used to determine the following petrophysical properties, density, magnetic susceptibility, primary wave velocity, resistivity, conductivity and chargeability. Moreover, the quantitative evaluation of minerals by scanning electron microscopy coupled with an automated image analysis system allowed us to map lithological and alteration processes. The results indicate density as the most effective physical property to map lithology, hydrothermal alteration and the Zn–Pb (Cu–Au) mineralization. Furthermore, all studied physical properties have moderate effectiveness in the alteration zones of known geological and geophysical anomalies in the Santa Maria deposit. Chargeability could be used, especially when sulphides are disseminated, but additional geological factors complicate its interpretation. The mineralogical and petrophysical diversity of the Santa Maria deposit provided vital data for geological–geophysical interpretations while allowing the creation of a key exploration plan to investigate the Zn–Pb (Cu–Au) mineralization. Finally, petrophysics should be used in prospection to help understand complex geological processes, their overlapping subpopulations and to accelerate mineral research while reducing the use of technical and financial resources and expenditure on ineffective geophysical methodologies.

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Section: Discussionmentioning

confidence: 99%

Section: Regional Geologymentioning

confidence: 99%

Petrophysics applied in mineralizations, hydrothermal alterations and lithology mapping: A case study from the Zn–Pb (Cu–Ag) epithermal deposit of Santa Maria, Brazil

Araújo

Silva

Barbosa

et al. 2022

Geophysical Prospecting

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“…A gênese do depósito de Santa Maria é controversa, pois autores consideram três diferentes hipóteses: 1) vulcanogênico distal (Biondi, 2015); 2) diagenética (Veigel & Dardenne, 1990); ou 3) magmática−hidrotermal . Para esta pesquisa será considerada a gênese magmática-hidrotermal, proposta por Hoerlle et al, (2019) e a partir da metodologia de geoquímica Pb-S em sulfetos e zircão U/Pb SHRIMP. Recentemente introduzido à literatura, o termo sulfetação intermediária (Sillitoe & Hedenquist, 2003), ao qual o Depósito Santa Maria se encaixa, descreve a mineralização distal equivalente à porção de temperatura mais baixa e de fluido menos ácido.…”

Section: Geologia Do Depósito Santa Mariaunclassified

Assinatura Geofísica e Geoquímica do Depósito Pb-Zn-(Cu-Ag) Santa Maria – RS, Brasil

et al. 2021

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O entendimento da assinatura geofísica em depósitos torna-se essencial na prospecção mineral, uma vez que a compreensão do footprint em profundidade é cada mais necessário devido a alvos e depósitos superficiais estarem cada vez mais escassos. A integração de outros tipos de dados aos dados geofísicos pode auxiliar na criação de processos de interpretações a partir do conhecimento avançado da resposta geofísica de diferentes rochas, alterações hidrotermais e mineralizações que futuramente podem aumentar a descoberta de novos alvos ou novas abordagens na prospecção. Esta pesquisa tem como alvo o depósito epitermal de Pb-Zn-(Cu-Ag) de Santa Maria, situado no distrito de Minas do Camaquã, município de Caçapava do Sul, Rio Grande do Sul, Brasil. Trata-se de um sistema magmático-hidrotermal distal, com mineralizações controladas por sistemas de falhas em arenitos e conglomerados, que hospedam zonas de alterações hidrotermais que contêm ilita, clorita e pirita, além de galena, esfalerita, calcopirita e bornita. O objetivo principal é mapear a assinatura geofísica do depósito a partir da integração de dados geoquímicos e geofísicos das rochas encaixantes, alterações hidrotermais e mineralizações. A metodologia inicial aplicada consiste na seleção de amostras de furos de sondagens representativas da litologia predominante, das rochas alteradas e das mineralizações hidrotermais do depósito; submissão das amostras a análises geoquímicas de elementos maiores, traço e terras raras; e aquisição de dados geofísicos para serem integrados e interpretados. A magnetometria terrestre, a resistividade e a polarização induzida mostraram-se eficientes para mapear a assinatura geofísica do Depósito Santa Maria, principalmente em termos estruturais, uma vez que se identificou o possível controlador de mineralizações da área. A geoquímica facilitou o entendimento das variações geofísicas, pois a presença de sulfetos em maiores quantidades e presença de óxidos como K2O, Al2O3 e MgO utilizados para mapear zonas de ilita e clorita, possibilitaram interpretações e associações à geofísica da área. Toda a integração de dados proporcionou uma maior confiabilidade na caracterização da assinatura geofísica do depósito.

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“…1). As pointed out by Hoerlle et al (2019), the terrane is "a Neoproterozoic metavolcanic-sedimentary sequence, represented by the Cambaizinho, Bossoroca and Palma Complexes intruded by juvenile calc-alkaline gneisses of the Cambaí Complex." The terrane was subdivided into different formations and complexes (e.g., Goñi et al 1962, Koppe et al 1985, Machado et al 1990, Babinski et al 1996, Saalmann et al 2006.…”

Section: ° Wmentioning

confidence: 99%

Mineralogical evolution of the northern Bossoroca ophiolite, São Gabriel terrane

et al. 2020

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Mineralogical evolution of ophiolites is significant to understand paleo-oceanic crust and mantle requiring multi-proxy techniques to identify steps in the processes. We studied the Bossoroca ophiolite from the southern Brasiliano Orogen, a prime example of Tonian accretion to an oceanic island arc. Integration of field geology, aeromagnetometry, aerogamaspectrometry, electron microprobe analyses, and compositional maps of minerals led to the decoding of oceanic and continental processes. The ophiolite is highly magnetic and low-K and is positioned at the base of the superstructure. We studied amphibolite, tourmalinite, and chromite-talc-magnesite granofels from the ophiolite, Capivaras diorite from the Cambaí Complex infrastructure and one metavolcanoclastic rock from the Vacacaí Group superstructure. Honblende is zoned in all rock types. Low-Ti hornblende is compatible with medium-pressure metamorphism at 7 kbar. This M1 to M2 amphibolite facies resulted in the widespread association of olivine + talc in metaserpentinite. Dravite is similar to tourmaline from the Ibaré ophiolite. Andesine and oligoclase are dominant and albite minor. Cr-spinel in granofels recrystallized in greenschist facies; host rock originated by carbonatization of serpentinite formed in the oceanic crust along with chloritite and tourmalinite. Serpentinite rare earth elements (REE) suggest origin in depleted mantle peridotite. The ophiolite evolved in the Adamastor Ocean until incorporation into the island arc.

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Evolution of fluorite-mica-feldspar veins: Evidences of a fossil geothermal system in the são Gabriel terrane and consequences for Pb-Zn-Cu metallogeny

Cited by 8 publications

References 50 publications

Petrophysics applied in mineralizations, hydrothermal alterations and lithology mapping: A case study from the Zn–Pb (Cu–Ag) epithermal deposit of Santa Maria, Brazil

Petrophysics applied in mineralizations, hydrothermal alterations and lithology mapping: A case study from the Zn–Pb (Cu–Ag) epithermal deposit of Santa Maria, Brazil

Assinatura Geofísica e Geoquímica do Depósito Pb-Zn-(Cu-Ag) Santa Maria – RS, Brasil

Mineralogical evolution of the northern Bossoroca ophiolite, São Gabriel terrane

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