Hostname: page-component-848d4c4894-jbqgn Total loading time: 0 Render date: 2024-06-24T11:03:24.388Z Has data issue: false hasContentIssue false
  • English
  • Français

Chronology and orientation of N2–CH4, CO2-H2O, and H2O-rich fluid-inclusion trails in intrametamorphic quartz veins from the Cuiabá gold district, Brazil

Published online by Cambridge University Press:  05 July 2018

C. J. S. de Alvarenga ,
M. Cathelineau  and
J. Dubessy
C. J. S. de Alvarenga
Affiliation:
Departamento de Geologia, Universidade Fed. de Mato Grosso, Cuiabá, 78100, Brazil
M. Cathelineau
Affiliation:
CREGU and GS CNRS-CREGU, BP 23, 54500, Vandoeuvre-les-Nancy, France
J. Dubessy
Affiliation:
CREGU and GS CNRS-CREGU, BP 23, 54500, Vandoeuvre-les-Nancy, France
Get access Rights & Permissions [Opens in a new window]

Abstract

The upper Proterozoic Cuiabá group of Mato Grosso, Brazil, is composed of low-grade clastic meta-sediments which have been folded by several successive tectonic events. Three generations of quartz veins are associated with the structural evolution of this area. The first veins are deformed by the main tectonic phases and show a complex deformational patterns. The second set is parallel to the cleavage and was formed syntectonically during the main folding phase, whilst the last quartz veins are related to a later stage of deformation. A systematic study of fluid inclusions in relation with a statistical study of microstructural markers (fluid inclusion trails, opened microcracks) was carried out on quartz veins from three localities. On the basis of microthermometric studies and Raman spectrometry analysis, four differents types of fluids have been distinguished, each trapped in specific fluid inclusion trails: (i) CO2-rich liquids and vapours (Lc, Vc) at Casa de Pedra, (ii) Lc and Vc inclusions with variable amounts of CO2, CH4, N2 in the vapour phase at BR-70, (iii) CH2-N2-rich vapours (Vn-m), and (iv) aqueous inclusions (L) with variable salinities representing the last fluid generations at all localities.

At Casa de Pedra and BR-70, most fluids are observed within the three generations of quartz veins, indicating an important fluid circulation associated with the last phase of brittle deformation. Fluid inclusions of type (iii) and (iv) are oriented along several well defined directions. The study shows the importance of integrated microstructural and fluid-inclusion studies for understanding the geometry and chronology of fluid circulation.

Keywords

fluid-inclusion trailsquartz veinsgoldBrazil
Type
Ore environments—gold mineralization
Information
Mineralogical Magazine , Volume 54 , Issue 375 , June 1990 , pp. 245 - 255
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1990

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

*

Present address: Lab. de Géologie Dynamique et Petrologie de la Surface, Centre de St. Jérôme, 13397 Marseille, France.

References

Almeida, F. F. M. de and Mantovani, M. S. M. (1975) Geologia e geocronologia do Granito São Vicente, Mato Grosso. Anais Acad. Brasileira Ciênc. 47, 451-8.Google Scholar
Alvarenga, C. J. S. de (1986) Evolução das deformações polifásicas brasilianas na Faixa Paraguai, região de Cuiabá, MT. In Anais 34th Congr. Brasileiro Geol., SBG. Goiânia, 3, 1170-5.Google Scholar
Alvarenga, C. J. S. de (1988) Turbiditos e a glaciaçãio do final do Proterozóico superior no Cinturão Paraguai, Mato Grosso. Rev. Brasileira Geociênc. 18, 323-7.CrossRefGoogle Scholar
Alvarenga, C. J. S. de and Trompette, R. (submitted) Glacially influenced turbidite sedimentation in the uppermost Proterozoic of the Paraguay belt (Mato Grosso, Brazil). J. Sedimen. Petrol. Google Scholar
Boiron, M. C., Cathelineau, M., Dubessy, J. and Bastoul, A. M. (1988) Proceedings of the SIMP meeting, Verbania, Italia, ‘Granites and their surroundings’, 1987. Rendiconti Soc. ltal. Min. Petrol. 43, 485-98.Google Scholar
Boiron, M. C., Cathelineau, M., Dubessy, J. and Bastoul, A. M. (1990) Fluids in Hercynian Auveins from the French Variscan belt. Mineral. Mag. 54, 231-43.CrossRefGoogle Scholar
Campos, E. G., Xavier, R. P. and Oliveira, S. M. B. de (1987) Caracterização dos fluidos mineralizantes relacionados aos veios de quartzo aurlferos do Grupo Cuiabá. 1 ° Congresso Brasileiro de Geoquímmica, Porto Alegre, 1987. Anais, 1, 417-35.Google Scholar
Crawford, M. L. and Hollister, L. S. (1986) Metamorphic fluids: the evidence from fluid inclusions. In Fluid-rock interactions during metamorphism (J. V. Walther and B. J. Wood, eds.. Advances in Physical Geochemistry>, 5, 1-35. Springer-Verlag. CrossRefGoogle Scholar
Dubessy, J., Poty, B. and Ramboz, C. (1989) Advances in C-O-H-N-S fluid geochemistry based on micro- Raman spectrometric analysis of fluid inclusions. Eur. J. Mineral 1, 517-34.CrossRefGoogle Scholar
French, B. M. (1966) Some geological implications of equilibrium between graphite and a C-H-O gas phase at high temperatures and pressures. Rev. Geophys. 4, 223-53.Google Scholar
Hasui, Y. and Almeida, F. F. M. de (1970) Geocronologia do centro-oeste brasileiro. Bol. Soc. Brasileira Geol., São Paulo, 19, 1-26.Google Scholar
Hubert, P. (1986) Texture et inclusions fluids des quartz aurifbres. Application au gite de Cross Gallet (Haute-Vienne, France) et au prospect de Sanoukou (District de Kinieba, Mali). Thèse Université d'Orleans.Google Scholar
Jacobs, G. K. and Kerrick, D. M. (1981) Methane: an equation of state with application to the ternary system H2O-CO2-CH4 system. Geochim. Cosmochim. Acta, 45, 607-14.CrossRefGoogle Scholar
Kerrick, D. M. and Jacobs, G. K. (1981) A remodified Redlich-Kwong equation for H2O , CO2 and H2O-CO2 mixtures at elevated pressures and temperatures. Am. J. Sci. 281, 735-67.CrossRefGoogle Scholar
Kowallis, B. J., Wang, H. F. and Jang, B. (1987) Healed microcrack orientations in granite from Illinois borehole UPH-3 and their relationship to the rock's stress history. Tectonophys. 135, 297-306.CrossRefGoogle Scholar
Lapique, M., Champenois, M. and Cheifletz, A. (1988) Un analyseur vidéographique interactif: description et applications. Bull. Minéral, 111, 679-87.CrossRefGoogle Scholar
Lespinasse, M. and Pêcher, A. (1986) Microffacturing and regional stress field: a study of the preferred orientations of fluid-inclusion planes in a granite from the Massif Central, France. J. Struct. Geol. 8, 169-80.CrossRefGoogle Scholar
Mullis, J. (1979) The system methane-water as a geologic thermometer and barometer from the external part of the Central Alps. Bull. Minéal. 102, 526-36.CrossRefGoogle Scholar
Mullis, J. (1987) Fluid-inclusion studies during very low-grade metamorphism. Low-temperature metamorphism (Frey, M., ed.), 162-99. Blackie.Google Scholar
Oltra, P. H. (1988) Une nouvelle méthode de quantification de la déformation subie par un échantillon. Apports du traitement numérique d'images et du illtrage de convolution. C. R. Acad. Sci. Paris, 306, 1493-9.Google Scholar
Pêcher, A., Lespinasse, M. and Leroy, J. (1985) Relations between fluid trails and regional stress field: a tool for fluid chronology—an example of an intragranitic uranium ore deposit (northwest Massif Central, France). Lithos, 18, 22-37.CrossRefGoogle Scholar
Potter, R. W. (1977) Pressure corrections for fluid inclusion homogenization temperatures based on volumetric properties of the system NaCl-H2O. J. Res. U.S. Geol. Surv. 6, 245-7.Google Scholar
Potter, R. W., Clynne, M. A. and Brown, D. L. (1978) Freezing point depression of aqueous sodium chloride solution. Econ. Geol. 73, 284-5.CrossRefGoogle Scholar
Poty, B., Leroy, J. and Jachimowicz, L. (1976) Un nouvel appareil pour la mesure des temperatures sous le microscope: l'installation de microthermométrie Chaix-Meca. Bull. Soc. Ft. Min. Crist. 99, 182-6.Google Scholar
Ramboz, C., Pichavant, M. and Weisbrod, A. (1982) Fluid immiscibility in natural processes: use and misuse of fluid inclusion data. Chem. Geol. 37, 29-48.CrossRefGoogle Scholar
Ramboz, C., Schnapper, D. and Dubessy, J. (1985) The P-V-T-X-fO2 evolution of H2O-CO2-CH4-bearing fluid in a wofframite vein: reconstruction from fluid inclusion studies. Geochim. Cosmochim. Acta, 49, 205-19.CrossRefGoogle Scholar
Roedder, E. (1984) Fhdd inclusions. Reviews in Mineralogy, 12, 644 pp. Min. Soc. America.Google Scholar
Tuttle, O. F. (1949) Structural petrology of planes of liquid inclusions. J. Geol. 57, 331-56.Google Scholar
Wise, D. U. (1964) Microjointing in basement, Middle Rocky Mountain of Montana and Wyoming. Bull. Geol. Soc. Am. 75, 287-306.CrossRefGoogle Scholar
Zhang, Y.-G. and Frantz, J. D. (1987) Determination of the homogenization temperatures and densities of supercritical fluids in the systems NaCl-KCl-CaCl2-H2O using synthetic fluid inclusions. Chem. Geol. 64, 335-50.CrossRefGoogle Scholar