Chemical (EPMA) and boron isotope (SIMS) analyses on tourmaline breccias from the Río Blanco-Los Bronces porphyry copper district, Chile

Hohf, Michael; Trumbull, Robert;

2022 || GFZ Data Services

Tourmaline-cemented magmatic-hydrothermal breccias are a major host to sulphide mineralization in the supergiant Río Blanco–Los Bronces (RB–LB) porphyry Cu-Mo district in central Chile. We made an extensive study of the chemical and boron isotopic composition of tourmaline from this district to shed light on the composition and origin of mineralizing fluids and to test the utility of tourmaline as an indicator mineral by comparing compositions from mineralized and barren breccias.

Río Blanco-Los Bronces is a world-class porphyry-type Cu-Mo district of late Miocene age hosted in a granodioritic batholith and related porphyry intrusions in central Chile (33°9’ S latitude, 70°17’W longitude). The porphyry intrusions and related orebodies are distributed along a structurally-controlled NW-SE zone. Mineralization comprises quartz-sulfide veins, disseminated sulfide miner-alization in altered porphyry host rocks and disseminated sulfides in hydrothermal breccias. See Toro et al. (2012) for an overview of the geology, geochronology and mineralization in the district.

Descriptions of the mineralized tourmaline breccias are given by Frikken et al. (2005) and Skewes et al. (2003). The data set provided here comprises in-situ chemical analyses of tourmaline by electron microprobe (EPMA) as well as in-situ boron-isotope analyses of tourmaline in the same samples by SIMS. Tourmaline was analysed in 12 samples including 8 from mineralized breccia bodies (Sur-Sur: 4, La Americana: 4), and 2 samples each from barren breccia and nearby granite-hosted tourmaline nodules in the Diamante area. We also give results of mass balance calculations testing the hypoth-esis of a magmatic-hydrothermal origin of the boron.

Originally assigned keywords

Corresponding MSL vocabulary keywords

MSL enriched keywords

MSL enriched sub domains
  • geochemistry
  • microscopy and tomography
Source http://dx.doi.org/10.5880/gfz.3.1.2022.002
Source publisher GFZ Data Services
DOI 10.5880/gfz.3.1.2022.002
Authors
  • Trumbull, Robert
  • 0000-0002-1999-4653
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
Contributors
  • Trumbull, Robert
  • ContactPerson
  • 0000-0002-1999-4653
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
  • Trumbull, Robert
  • DataCollector
  • 0000-0002-1999-4653
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
  • Solé, Marco
  • RelatedPerson
  • CODELCO-Chile, División Andina, Los Andes, Chile;
  • Microprobe Laboratory (GFZ German Research Centre for Geosciences, Germany)
  • HostingInstitution
  • GFZ German Research Centre for Geosciences. Potsdam, Germany;
  • Potsdam Ion Microprobe (SIMS) User Facility (GFZ German Research Centre for Geosciences, Germany)
  • HostingInstitution
  • GFZ German Research Centre for Geosciences. Potsdam, Germany;
  • Trumbull, Robert
  • ContactPerson
  • GFZ German Research Centre for Geosciences. Potsdam, Germany;
References
  • Cites
  • Dyar, M. D., Wiedenbeck, M., Robertson, D., Cross, L. R., Delaney, J. S., Ferguson, K., Francis, C. A., Grew, E. S., Guidotti, C. V., Hervig, R. L., Hughes, J. M., Husler, J., Leeman, W., McGuire, A. V., Rhede, D., Rothe, H., Paul, R. L., Richards, I., & Yates, M. (2001). Reference Minerals for the Microanalysis of Light Elements. Geostandards Newsletter, 25(2–3), 441–463. Portico. https://doi.org/10.1111/j.1751-908x.2001.tb00616.x
  • 10.1111/j.1751-908X.2001.tb00616.x
  • Cites
  • Frikken, P. H., Cooke, D. R., Walshe, J. L., Archibald, D., Skarmeta, J., Serrano, L., & Vargas, R. (2005). Mineralogical and Isotopic Zonation in the Sur-Sur Tourmaline Breccia, Rio Blanco-Los Bronces Cu-Mo Deposit, Chile: Implications for Ore Genesis. Economic Geology, 100(5), 935–961. https://doi.org/10.2113/gsecongeo.100.5.935
  • 10.2113/gsecongeo.100.5.935
  • Cites
  • Skewes, M. A., Holmgren, C., & Stern, C. R. (2002). The Donoso copper-rich, tourmaline-bearing breccia pipe in central Chile: petrologic, fluid inclusion and stable isotope evidence for an origin from magmatic fluids. Mineralium Deposita, 38(1), 2–21. https://doi.org/10.1007/s00126-002-0264-9
  • 10.1007/s00126-002-0264-9
  • Cites
  • Cites
  • Yavuz, F., Karakaya, N., Yıldırım, D. K., Karakaya, M. Ç., & Kumral, M. (2014). A Windows program for calculation and classification of tourmaline-supergroup (IMA-2011). Computers & Geosciences, 63, 70–87. https://doi.org/10.1016/j.cageo.2013.10.012
  • 10.1016/j.cageo.2013.10.012
  • Cites
  • Hohf, M., Trumbull, R. B., Cuadra, P., & Solé, M. (2023). Tourmaline Breccias from the Río Blanco-Los Bronces Porphyry Copper District, Chile: Constraints on the Fluid Source and the Utility of Tourmaline Composition for Exploration. Economic Geology, 118(4), 779–800. https://doi.org/10.5382/econgeo.4991
  • 10.5382/econgeo.4991
  • IsSupplementTo
Contact
  • Trumbull, Robert
  • GFZ German Research Centre for Geosciences. Potsdam, Germany;
  • Trumbull, Robert
  • GFZ German Research Centre for Geosciences. Potsdam, Germany;
Citation Hohf, M., & Trumbull, R. (2022). Chemical (EPMA) and boron isotope (SIMS) analyses on tourmaline breccias from the Río Blanco-Los Bronces porphyry copper district, Chile [Data set]. GFZ Data Services. https://doi.org/10.5880/GFZ.3.1.2022.002
Geo location(s)
  • Study are in the Río Blanco-Los Bronces porphyry copper district, Chile
Spatial coordinates
  • eLong -70.2
  • nLat -33.1
  • sLat -33.2
  • wLong -70.3