Fluid Geochemistry and Mineralogy in Volcanic/Hydrothermal Environments

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Geochemistry and Geochronology".

Deadline for manuscript submissions: closed (31 March 2023) | Viewed by 4598

Special Issue Editors


E-Mail Website
Guest Editor
Instituto de Ciencias de la Ingeniería, Universidad de O’Higgins, Rancagua 2841959, Chile
Interests: isotope geochemistry; fluid geochemistry; environmental geochemistry; economic geology

E-Mail Website
Guest Editor
Università degli Studi di Urbino Carlo Bo, Dipartimento di Scienze Pure e Applicate, Urbino, Italy
Interests: environmental geochemistry; isotope geochemistry; geoexchange potential; geothermal energy; groundwater
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Institute of Geosciences and Earth Resources (IGG), National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Florence, Italy
Interests: environmental geochemistry; mercury pollution; hydrogeochemistry; fluid geochemistry; air and water quality
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The aim of the present Special Issue is to gather original articles focusing on the geochemistry of fluids (gas and water) and isotopes, as well as mineralogical studies in volcanic and active/fossil hydrothermal systems.

This Special Issue will comprise different fields of the discipline and a broad range of relevant topics of interest, including:

  1. Fluid geochemistry and mineralogy applied to geothermal exploration;
  2. Geochemical monitoring of active volcanoes;
  3. Isotopic geochemistry of fluids in hydrothermal/volcanic environments;
  4. Fluid inclusions in active and fossil hydrothermal systems;
  5. Hydrothermal alteration in active geothermal fields;
  6. Organic and inorganic compounds flux emissions in volcanic/hydrothermal environment;
  7. Critical elements recovery from geothermal brines;
  8. Geochemistry and mineralogy of hydrothermal ore deposits;
  9. Environmental impact and human hazard of volcanic and hydrothermal fluids;
  10. Geothermometry/geobarometry;
  11. Water and mineral geochronological application to hydrothermal/volcanic systems;
  12. Water–gas–rock interaction in faults and fractures.

Dr. Daniele Tardani
Dr. Marco Taussi
Dr. Jacopo Cabassi
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • fluid geochemistry
  • isotopic geochemistry
  • geothermal exploration
  • volcanic degassing
  • geochronology
  • hydrothermal systems

Published Papers (2 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

33 pages, 34009 KiB  
Article
Hydrothermal Alteration in the Nevados de Chillán Geothermal System, Southern Andes: Multidisciplinary Analysis of a Fractured Reservoir
by Diego Morata, Romina Gallardo, Santiago Maza, Gloria Arancibia, Camila López-Contreras, Valentina Mura, Claudia Cannatelli and Martin Reich
Minerals 2023, 13(6), 722; https://doi.org/10.3390/min13060722 - 25 May 2023
Cited by 1 | Viewed by 1963
Abstract
The interplay between a heat source, primary plus secondary permeability, and hydrothermal fluids makes geothermal systems a highly dynamic environment where evolving physico-chemical conditions are recorded in alteration mineralogy. A comprehensive characterization of hydrothermal alteration is therefore essential to decipher the major processes [...] Read more.
The interplay between a heat source, primary plus secondary permeability, and hydrothermal fluids makes geothermal systems a highly dynamic environment where evolving physico-chemical conditions are recorded in alteration mineralogy. A comprehensive characterization of hydrothermal alteration is therefore essential to decipher the major processes associated with geothermal system development. In this study, we defined the hydrothermal mineralogical evolution of the Nevados de Chillán Geothermal System (NChGS), located in the Southern Volcanic Zone (SVZ) of the central Andes, where the regional framework of the system is formed by a direct association with a currently active volcanic complex, a favorable structural control, and vertically inhibited fluid circulation. To characterize the secondary mineralogy present in the NChGS, we integrated optical petrography, Scanning Electron Microscopy (SEM) observations, X-ray Diffraction (XRD) analysis, and microthermometric measurements along a drill core with a depth of 1000 m at the Nieblas-1 well. These mineralogical approaches were combined with a structural field analysis to highlight the relevance of multidisciplinary study in understanding active geothermal systems. The results indicated that the evolution of the system involved four paragenetic stages, with the main processes in each phase being the heating, boiling, and mixing of fluids and re-equilibration to new physico-chemical conditions. Additionally, three hydrothermal zones were recognized: an upper argillic section, an intermediate sub-propylitic zone, and a deep propylitic domain. Sampled thermal springs are characterized by pH values of 2.4–5.9 and high SO4= concentrations (>290 ppm). These acid-sulfate steam-heated waters suggest the contribution of primary magmatic volatiles to the hydrothermal system. Alunite recorded in the alteration halos of veinlets presents at depths of 170–230 m denote the circulation of acidic fluids at these levels which were favored by reverse faults. These findings indicate that, at this depth range, the condensation of magmatic volatiles into shallow aquifers controls the recharge area of the superficial thermal manifestations. Conversely, deep-seated hydrothermal fluids correspond to near-neutral chloride fluids, with salinities ranging from 0.1 to 6.9 wt.% NaCl eq. The distribution of illite/smectite and chlorite/smectite mixed-layered minerals outline the presence of a significant clay cap, which, in this system, separates the steam-heated domain from the deep hydrothermal realm and restricts fluid circulation to existing permeable channels. Our mineralogical and structural study provides critical data for the interpretation of heat–fluid–rock interaction processes in the NChGS. The interplay between hydrothermal fluids and active faults is also discussed in the context of the complex of geological processes in active geothermal systems along the Chilean Southern Volcanic Zone. Full article
Show Figures

Figure 1

18 pages, 5285 KiB  
Article
Clay Minerals in the Deep Reservoir of the Cerro Pabellón Geothermal System (Northern Chile)
by Jeanne Vidal, Patricia Patrier, Daniel Beaufort, Santiago Maza, Germain Rivera, Gianni Volpi and Diego Morata
Minerals 2022, 12(10), 1244; https://doi.org/10.3390/min12101244 - 29 Sep 2022
Cited by 2 | Viewed by 1789
Abstract
This study focuses on hydrothermal alteration, and more specifically clays, in the geothermal reservoir of Cerro Pabellón in Andean Cordillera, Northern Chile. Although it is the first commercial geothermal power plant in South America with 48 MWe installed and an additional 33 MWe [...] Read more.
This study focuses on hydrothermal alteration, and more specifically clays, in the geothermal reservoir of Cerro Pabellón in Andean Cordillera, Northern Chile. Although it is the first commercial geothermal power plant in South America with 48 MWe installed and an additional 33 MWe during 2022, the alteration mineralogy of the deep reservoir remains poorly investigated. Cuttings from two deep wells drilled between 500 and 3000 m depth were sampled. The fine-grained clay fraction was analyzed using X-ray diffraction to observe the mineral distribution and variations of crystal structure of the clays. Scanning electron microscopy coupled with energy dispersive spectroscopy allowed us to perform microanalysis of the clays. The results suggest a high heterogeneity of the reservoir in term of alteration: a pervasive alteration dominated by trioctahedral clays was observed in all the samples, whereas a fracture-controlled alteration was only observed locally, dominated by dioctahedral clays. Illite-smectite mixed layers with more than 90% illite typically occur in permeable fracture and fault as a typical clay signature. This study completed an integrated conceptual model of the high enthalpy reservoir (>250 °C). Circulations of a neutral pH Na-K-Cl fluid occur in a wide fracture system connected to highly dipping and NW-striking faults and could extend beyond the Pabelloncito graben. Full article
Show Figures

Figure 1

Back to TopTop