Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-23T07:31:32.708Z Has data issue: false hasContentIssue false
  • English
  • Français

Fluid inclusions in amethyst quartz of different geological environments from Brazil

Published online by Cambridge University Press:  19 April 2021

Coralie Heinis Dias Open the ORCID record for Coralie Heinis Dias [Opens in a new window] ,
Mario Luiz de Sá Carneiro Chaves ,
Rosaline Cristina Figueiredo e Silva  and
Sylvio Dutra Gomes
Coralie Heinis Dias*
Affiliation:
Universidade do Estado de Minas Gerais, Departamento de Geociências, Ciências Humanas e Linguagens, Av. Brasília, 1304, Bairro Baú, João Monlevade, Minas Gerais, 35930-314, Brazil
Mario Luiz de Sá Carneiro Chaves
Affiliation:
Universidade Federal de Minas Gerais, Departamento de Geologia, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil
Rosaline Cristina Figueiredo e Silva
Affiliation:
Universidade Federal de Minas Gerais, Departamento de Geologia, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil
Sylvio Dutra Gomes
Affiliation:
Universidade Federal da Bahia, Instituto de Geociências, R. Barão de Jeremoabo, s/n, Ondina, Salvador, Bahia, 40170-290, Brazil.
*
*Author for correspondence: Coralie Heinis Dias, Email: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Fluid-inclusion studies were conducted on amethyst quartz from three different geological environments: basalt cavities; hydrothermal veins; and granitic pegmatites of Eastern Brazil, to understand the conditions of amethyst crystallisation in each of these environments. In samples from basalt cavities, fluid inclusions are exclusively one-phase aqueous types suggesting a low-temperature formation environment. Crystals from the two other environments show that fluid inclusions can be either one-phase aqueous, two-phase aqueous, three-phase aqueous carbonic, or three-phase aqueous with the presence of precipitated solid halite. The carbonic composition of the system H2O–CO2–NaCl was confirmed by Raman spectroscopic analysis and suggests a metamorphic or magmatic fluid source. Fluid inclusions trapped in samples from hydrothermal veins reveal at least two different fluid generations based on homogenisation temperatures. The first generation has minimum trapping temperatures between 249°C and 391°C. The second generation of lower temperature fluids has minimum trapping temperatures varying from 82°C to 203°C. Fluid inclusions of this group record eutectic temperatures that indicate the presence of Ca and Fe cations in addition to Na. Fluid inclusions trapped in amethyst from a pegmatite body have moderate salinity values between 15 and 25 eq. wt.% NaCl, thus reflecting the elevated salt content in pegmatite-forming fluids. In this sample, the first fluid generation is represented by aqueous fluid inclusions with minimum trapping temperatures ranging from 268°C to 375°C. The estimated eutectic temperatures, generally below –50°C, indicate the presence of Ca cations in addition to Na. Minimum trapping temperatures correspond to temperatures of late-to-post-pegmatitic hydrothermal stages. The second generation records minimum trapping temperatures between 125°C and 247°C. Amethyst from both hydrothermal veins and pegmatite environments contain solid inclusions of hematite, an indication that the mineralising fluid was Fe rich and thus, possibly magmatic in origin.

Keywords

fluid inclusionsamethystbasalthydrothermal veinpegmatite
Type
Article
Information
Mineralogical Magazine , Volume 85 , Issue 3 , June 2021 , pp. 332 - 347
Copyright
Copyright © The Author(s), 2021. Published by Cambridge University Press on behalf of The Mineralogical Society of Great Britain and Ireland

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

Associate Editor: Daniel Atencio

References

Almeida, F.F.M. (1977) O cráton do São Francisco. Revista Brasileira de Geociências, 7, 349–364.Google Scholar
Bodnar, R.J. (2003) Introduction to fluid inclusions. Pp. 1–8 in: Fluid Inclusions: Analysis and Interpretation (Samson, I., Anderson A, A.. and Marshall, D., editors). Mineralogical Association of Canada, Quebec.Google Scholar
Bodnar, R.J. and Vityk, M.O. (1994) Interpretation of microthermometric data for H2O–NaCl fluid inclusions. Pp. 117–130 in: Fluid Inclusions in Minerals: Methods and Applications (de Vivo, B., Frezzotti, M.L., editors). Short Course IMA, Blacksburg, USA.Google Scholar
Bowers, T.S. and Helgeson, H.C. (1983) Calculation of the thermodynamic and geochemical consequences of nonideal mixing in the system H2O–CO2–NaCl on phase relations in geological systems: equation of state for H2O–CO2–NaCl fluids at high pressures and temperatures. Geochimica et Cosmochimica Acta, 47, 1247–1275.10.1016/0016-7037(83)90066-2CrossRefGoogle Scholar
Brown, P.E. and Hagemann, S.G. (1995) MacFlinCor and its application to fluids in Archean lode–gold deposits. Geochimica et Cosmochimica Acta, 59, 3943–3952.10.1016/0016-7037(95)00254-WCrossRefGoogle Scholar
Chaves, M.L.S.C. and Coutinho, D.C. (1992) Nota sobre a jazida de ametista da Fazenda Sobrado (Felício dos Santos – MG). REM: Revista Escola de Minas, 45, 194–195.Google Scholar
Chaves, M.L.S.C., Tolentino, E.L. Jr., Dias, C.H.D. and Romano, A.W. (2017) Geologia, mineralogia, inclusões fluidas e gênese dos depósitos de titanita–epidoto de Capelinha, Minas Gerais. Geologia USP Série Científica, 17, 3–18.10.11606/issn.2316-9095.v17-124587CrossRefGoogle Scholar
Cohen, A.J. (1985) Amethyst color in quartz, the result of radiation protection involving iron. American Mineralogist, 70, 1180–1185.Google Scholar
Cohen, A.J. and Hassan, F. (1974) Ferrous and ferric ions in synthetic alpha-quartz and natural amethyst. American Mineralogist, 59, 719–728.Google Scholar
Commin-Fischer, A., Berger, G., Polvé, M., Dubois, M., Sardini, P., Beaufort, D. and Formoso, M. (2010) Petrography and chemistry of SiO2 filling phases in the amethyst geodes from the Serra Geral Formation deposit, Rio Grande do Sul, Brazil. Journal of South American Earth Sciences, 29, 751–760.10.1016/j.jsames.2009.10.002CrossRefGoogle Scholar
Cox, R.T. (1977) Optical absorption of the d4 ion Fe4+ in pleochroic amethyst quartz. Journal of Physics C Solid State Physics, 10, 4631.10.1088/0022-3719/10/22/032CrossRefGoogle Scholar
Dardenne, M.A. and Schobbenhaus, C. (2003) Depósitos minerais no tempo geológico e épocas metalogenéticas. Pp. 365–447 in: Geologia, tectônica e recursos minerais do Brasil: texto, mapas e SIG (Bizzi, L.A., Schobbenhaus, C., Vidotti, R.M. and Gonçalves, J.H., editors). Companhia de Pesquisa de Recursos Minerais, Brasília.Google Scholar
Dedushenko, S.K., Makhina, I.B., Mar'in, A.A., Mukhanov, V.A. and Perfiliev, Y.U.D. (2004) What oxidation state of iron determines the amethyst colour? Hyperfine Interactions, 156, 417–422.10.1023/B:HYPE.0000043262.10503.8aCrossRefGoogle Scholar
Dennen, W.H. and Puckett, A.M. (1972) On the chemistry and color of amethyst. The Canadian Mineralogist, 11, 448–456.Google Scholar
Dias, C.H., Chaves, M.L.S.C., Juchem, P.L. and Romano, A.W. (2019) Ocorrências de ametista em basaltos do Triângulo Mineiro (Minas Gerais): comparações com depósitos similares do Rio Grande do Sul. Pesquisas em Geociências, 46, e0822. doi:10.22456/1807-9806.97385CrossRefGoogle Scholar
Dodd, S.C., Macniocaill, C. and Muxworthy, A.R. (2015) Long duration (>4Ma) and steady-state volcanic activity in the early Cretaceous Paraná-Etendeka Large Igneous Province: New paleomagnetic data from Namibia. Earth and Planetary Science Letters, 414, 16–29.10.1016/j.epsl.2015.01.009CrossRefGoogle Scholar
Dumanska-Slowik, M, Tobola, T., Jarmolowicz-Szulc, K., Naglik, B., Dylag, J. and Szczerba, J. (2017) Inclusion study of hourglass amethyst from Boudi (Morocco) by Raman microspectroscopy and microthermometric measurements. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 187, 156–162.10.1016/j.saa.2017.06.053CrossRefGoogle ScholarPubMed
Fischer, A.C., Krambrock, K., Pinheiro, M.V.B. and Juchem, P.L. (1999) Natural and irradiated amethyst from Rio Grande do Sul studied by optical absorption and electron paramagnetic resonance. Anais da Academia Brasileira de Ciências, 71, 823–824.Google Scholar
Fogaça, A.C.C. (2012) Folha Diamantina, SE.23–Z–A–III, escala 1:100.000. Convênio CODEMIGUFMG, Belo Horizonte.Google Scholar
Frank, H.T., Gomes, M.E.B. and Formoso, M.L.L. (2009) Revisão da extensão areal e do volume da formação Serra Geral, Bacia do Paraná, América do Sul. Pesquisas em Geociências, 36, 49–57.10.22456/1807-9806.17874CrossRefGoogle Scholar
Frezzotti, M.L., Tecce, F. and Casagli, A. (2012) Raman spectroscopy for fluid inclusion analysis. Journal of Geochemical Exploration, 112, 1–20.10.1016/j.gexplo.2011.09.009CrossRefGoogle Scholar
Gilg, H.A. (2012) In the beginning: The origins of amethyst. Pp. 10–13 in: Amethyst – Uncommon Vintage (Balzer, R. and Gilg, H.A., editors). Lithographie, Denver.Google Scholar
Gilg, H.A., Morteani, G., Kostitsyn, Y., Preinfalk, C., Gatter, I. and Strieder, A.J. (2003) Genesis of amethyst geodes in basaltic rocks of the Serra Geral Formation (Ametista do Sul, Rio Grande do Sul, Brazil): a fluid inclusion, REE, oxygen, carbon, and Sr isotope study of basalt, quartz and calcite. Mineralium Deposita, 38, 1009–1025.10.1007/s00126-002-0310-7CrossRefGoogle Scholar
Goldstein, R.H. and Reynolds, T.J. (1994) Systematics of Fluid Inclusions in Diagenetic Minerals. Society for Sedimentary Geology Short Course 31, 199 pp.10.2110/scn.94.31CrossRefGoogle Scholar
Juchem, P.L. (1999) Mineralogia, geologia e gênese dos depósitos de ametista da região do Alto Uruguai, Rio Grande do Sul. PhD Thesis, Universidade de São Paulo, São Paulo, Brazil.Google Scholar
Juchem, P.L. (2013) O Distrito Mineiro de Ametista do Sul – roteiro de excursão. Pp. 7–15 in: Seminário Brasileiro de Gemologia e Design de Joias, 3.Google Scholar
Juchem, P.L., Hofmeister, T., Brum, T.M.M. (1990) Substâncias gemológicas no Rio Grande do Sul – modos de ocorrência e caracterização gemológica. Pp. 1436–1449 in: Congresso Brasileiro de Geologia, 36.Google Scholar
Lehmann, G. and Moore, W.J. (1966) Color center in amethyst quartz. Science, 152, 1061–1062.10.1126/science.152.3725.1061CrossRefGoogle ScholarPubMed
Leite, C.A.S. et al. (2004). Folha SE.24-Rio Doce in: Carta Geológica do Brasil ao Milionésimo (Schobbenhaus, C., Gonçalves, J.H., Santos, J.O.S., Abram, M.B., Leão Neto, R., Matos, G.M.M., Vidotti, R.M., Ramos, M.A.B. and de Jesus, J.D.A., editors). CPRM, Brasília.Google Scholar
London, D. (2008) Pegmatites. Mineralogical Association of Canada, Québec, 347 pp.Google Scholar
London, D. and Kontak, D.J. (2012) Granitic pegmatites: scientific wonders and economic bonanzas. Elements, 8, 257–261.10.2113/gselements.8.4.257CrossRefGoogle Scholar
Pedrosa-Soares, A.C., Chaves, M.L.S.C. and Scholz, R. (2009) Field Trip Guide. Pp 1–28 in: International Symposium on Granitic Pegmatites. PEG2009, Belo Horizonte, Brazil, August 2009.Google Scholar
Pedrosa-Soares, A.C. et al. (2011) Late Neoproterozoic–Cambrian granitic magmatism in the Araçuaí orogen (Brazil), the Eastern Brazilan Pegmatite Province and related deposits. Geological Society Special Publication, 350, 25–51.10.1144/SP350.3CrossRefGoogle Scholar
Piccirillo, E.M. and Melfi, A.J. (1988) Mesozoic Flood Volcanism of the Paraná Basin: Petrogenetic and Geophysical Aspects. IAG–USP, São Paulo, Brazil, 600 pp.Google Scholar
Pinto, C.P. and Silva, M.A. (2014) Mapa Geológico do Estado de Minas Gerais, escala 1:1.000.000. Convênio CODEMIG/CPRM–SGB, Belo Horizonte, Brazil.Google Scholar
Ramboz, C., Pichavant, M. and Weisbrod, A. (1982) Fluid immiscibility in natural processes: Use and misuse of fluid inclusion data II. Interpretation of fluid inclusion data in terms of immiscibility. Chemical Geology, 37, 29–48.Google Scholar
Scholz, R., Chaves, M.L.S.C., Krambrock, K., Pinheiro, M.V.B., Barreto, S.B. and Menezes, M.G. (2012) Brazilian quartz deposits with special emphasis on gemstone quartz and its color treatment. Pp 139–159 in: Quartz: Deposits, Mineralogy and Analytics (Götze, J. and Möckel, R., organisers). Springer–Verlag Berlin Heidelberg, New York.10.1007/978-3-642-22161-3_6CrossRefGoogle Scholar
Shepherd, T.J., Rankin, A.H. and Alderton, D.M. (1985) A Practical Guide to Fluid Inclusion Studies. Blackie, Glasgow, UK, 239 pp.Google Scholar
Thiede, D.S. and Vasconcelos, P.M. (2010) Paraná flood basalts: Rapid extrusion hypothesis confirmed by new 40Ar/39Ar results. Geology, 38, 747–750.10.1130/G30919.1CrossRefGoogle Scholar
Tupinambá, M., Baars, F.J., Uhlein, A., Grossi-Sad, J.H. and Knauer, L.G. (1996) Folha Rio Vermelho, Mapa e Nota Explicativa. Comig–UFMG, Belo Horizonte, Brazil.Google Scholar
Tupinambá, M., Baars, F.J., Uhlein, A., Grossi-Sad, J.H. and Knauer, L.G. (2012) Folha Rio Vermelho, SE.23–Z–B–I, escala 1:100.000 . Convênio CODEMIGUFMG, Belo Horizonte, Brazil.Google Scholar
Valente, C.R., Lacerda Filho, J.F., Rizzotto, G.J., Lopes, R.C., Romanini, S.J., Oliveira, I.W.B., Sachs, L.L.B., Silva, V.A. and Batista, I.H. (2004) Folha SE.22-Goiânia in: Carta Geológica Brasil ao Milionésimo (Schobbenhaus, C., Gonçalves, J.H., Santos, J.O.S., Abram, M.B., Leão Neto, R., Matos, G.M.M., Vidotti, R.M., Ramos, M.A.B. and de Jesus, J.D.A., editors). CPRM, Brasília.Google Scholar
Vieira, V.S., Silva, M.A., Corrêa, T.R. and Lopes, NHB (2013) Mapa geológico do Estado do Espírito Santo, escala 1:400.000. CPRM, Belo Horizonte, Brazil.Google Scholar
Yang, K.H., Yun, S.H. and Lee, J.D. (2001) A fluid inclusion study of an amethyst deposit in the Cretaceous Kyongsang Basin, South Korea. Mineralogical Magazine, 65, 477–487.10.1180/002646101750377515CrossRefGoogle Scholar
Yardley, B.W.D. (1983) Quartz veins and devolatilization during metamorphism. Journal of the Geological Society of London, 140, 657–663.10.1144/gsjgs.140.4.0657CrossRefGoogle Scholar